you'd think developers would remove these problems at first instead of letting them accumulate and 'inhibit' more and more development. if these super slow terrain pieces made development 10x slower, why weren't they removed from the start? i fully support the way people are voicing their opinions making these topics. this is what happens when you cut features that players are already accustomed to this far into a game's life. see: runescape wilderness riot
how would they know it'd be a detriment to development of features they haven't even started on yet? perhaps not even planned? that's not how coding works.
badspot didn't make the engine, and definitely didn't go into BL knowing the exact C++ workings of it. it was probably realised later on that they were becoming an inconvenience and waited awhile before pulling the trigger on removing them.
though obviously i'm not badspot and am certainly not close enough to any of the developers to know any of this for sure. it's just an educated guess.
voicing your opinion is fine, but a good few of the topics discussing this subject have been more along the lines of "whining". which is a blunt term for being bad at voicing your opinion.
if someone wants to actually put thought and research into their opinion and post an actual good argument that's fine
if they're just saying "ugh why did the devs do that please put it back god" i don't see why they should even be payed attention to
and terrain+interiors are actually pretty good for some reasons. but i think the logical weighing of good and bad (forsaking aesthetics for this because they can be pretty risky to include for this kind of thing) would suggest that after v21 changes, the game is probably not 'much better off', but not 'worse off'.