Overdoing it does seem quite likely - if I didn't know and was trying to do a test I could easily see myself just enabling all the optimizations and moving on.

I would as well. My understanding is that SystemD does more parallelization/magic to decrease boot time, but is a bigger system to try to comprehend and has more surface in general.

I believe parallelization is a configurable option on OpenRC though, I'll add that test to the list to try some time.