There are very few technologies that are wholly hard or wholly soft, at least when viewed as an assembly. It is the proportion of soft/hard parts that make a particular assembly softer or harder. That's how come replacement can make things harder and aggregation can make things softer. When we replace, we take something from the technology assembly that was formerly flexible and negotiable and make it less so. When we aggregate, we make no changes to the assembly that was there before but we increase the adjacent possible and thus enable more human choice and active shaping of the technology. To help clarify, here is a simple example of how we might harden and soften an assessment activity in a course:

1. soft: Tell the learners to pass their work to you when they are ready. You will tell them what you think
2. harder: Tell the learners to pass their work to you when they are ready. You will grade them according to a set of criteria
3. harder: Tell the learners to pass their work to you on or before a certain date and time. You will grade them according to a set of criteria
4. harder: Tell the learners to pass their work to you on or before a certain date and time in PDF format. You will grade them according to a set of criteria
5. harder: Tell the learners to pass their work to you on or before a certain date and time in PDF format, presenting you with no more than 1500 words. You will grade them according to a set of criteria
6. harder: Tell the learners to pass their work to you on or before a certain date and time in PDF format, presenting you with no more than 1500 words, structured with an introduction, literature review, discussion and conclusion, with correct citations in APA format . You will grade them according to a set of criteria.
7. harder: Give the learners a templates set of questions that they must answer in essay form with fixed word limits. You will grade them according to a set of criteria.
8. harder: Put the whole thing in an LMS and use an LSA-based automated marking system to provide feedback and results, according to criteria programmed into the machine. 
9. Put the whole thing in an LMS and use an LSA-based automated marking system to provide feedback and results, according to criteria programmed into the machine. Late submissions receive an automatic mark of zero. Results are automatically added to a student record sheet without teacher intervention.

Notice that, each time, we replace one flexible part of the technology with another, less flexible part. Logic would suggest that we should simply reverse that procedure to soften things again but, once we start down this kind of path we tend to create a set of path dependencies and  systemic interdepenencies and patterns that affect not only the technology we are looking at but the technologies of which it is a part and those with which it interacts. Typically, this kind of pattern would be accompanied by regulations, processes, tools, learner expectations and policies that would make it trickier to reverse than it was to create. Also, we would seldom want to throw away everything we have gained by hardening and start afresh. If that's not the case then all is well, we can modify things back to a softer state if that's what we need. And that would be lovely. But what if we wanted to keep some of the good things from the harder system while enabling alternative and more flexible approaches where needed? Or if other systems (e.g. the pedagogies of the class, the regulations of the course etc) had been built around the harder system? There is another way, using aggregation, that provides a more flexible and simpler-to adapt method of softening. Here is the beginnings of a similar list that reverses parts of the hardness by adding extra technologies:

1. softer: Put the whole thing in an LMS and use an LSA-based automated marking system to provide feedback and results, according to criteria programmed into the machine. Late submissions receive an automatic mark of zero.  Results are automatically added to a student record sheet without teacher intervention. The results produced by the system are treated as provisional. Students must print their records and take them to the tutor for a signature before they are officially recognised. The tutor may manually amend the marks, and sign the amendment to avoid fraud. The tutor may also manually mark an assignment that has received zero for late submission, if the student provides an acceptable excuse
2. softer: Put the whole thing in an LMS and use an LSA-based automated marking system to provide feedback and results, according to criteria programmed into the machine. Late submissions receive an automatic mark of zero.  Results are automatically added to a student record sheet without teacher intervention.The results produced by the system are treated as provisional. Students must print their records and take them to the tutor for a signature before they are officially recognised. The tutor may manually amend the marks, and sign the amendment to avoid fraud. The tutor may also manually mark an assignment that has received zero for late submission, if the student provides an acceptable excuseBefore the tutor will sign it, he or she is optionally given a reflective document produced by the student that describes the process. The document gives the student a chance to explain answers in ways that were not possible using the automated form.
3. softer: Put the whole thing in an LMS and use an LSA-based automated marking system to provide feedback and results, according to criteria programmed into the machine. Late submissions receive an automatic mark of zero.  Results are automatically added to a student record sheet without teacher intervention.The results produced by the system are treated as provisional. Students must print their records and take them to the tutor for a signature before they are officially recognised. The tutor may manually amend the marks, and sign the amendment to avoid fraud. The tutor may also manually mark an assignment that has received zero for late submission, if the student provides an acceptable excuseBefore the tutor will sign it, he or she is optionally given a reflective document produced by the student that describes the process. The document gives the student a chance to explain answers in ways that were not possible using the automated form. If the student wishes, he or she may submit an essay-form version of the answers, formatted according to recognised academic standards. The tutor may choose to treat that as the submission instead of the original automated work.
4. etc

Note that, though it looks much more complex and full of redundancies this can, with a sufficiently technically advanced component-based system, be at least partially automated  without too much hassle. Using this kind of approach we can selectively soften different parts of the system without necessarily having to roll back the whole thing and lose the hard parts that we value. But soft is indeed hard. The paragraphs describing the technologies are now longer because we are now combining more technologies to achieve the same (but more attuned to our needs) result, and introducing redundancies and complexities for teacher and students that may make it unworthwhile. That's the trade-off, of course, the reason we need to think about just how soft or hard we would like our systems to be. There are no generalisable right answers here, but our technologies must be sufficiently malleable to allow us to shift the amount of softness and hardness in them according to our ever-changing needs. Without such malleability, we risk being slaves to the machine or floundering in unnecessarily inefficient complexities and substandard tools that are a poor fit with what we want to do