In hindsight yes. That said Obj 187 was also intended to use a new engine so that would have required quite an investment in new tooling even if the new turret itself was already "paid for" with T-90A and T-90M (and arguably part of the engine investment was paid for with V-92 IRL, ignoring the option to even use V-92 or a similar V-XX evolution in a modified 187), so the govt probably still balked at the idea back then, as all that investment would be concentrated in the 90s when the economy was worst.
New Engine was from variant #4. Even then, you can have bigger engine compartment and still use old V2-type engine, in fact, it would be a boon, as IIRC V92S2F main limitation in power is first by cooling capacity. Also more psace for better transmisiion etc.
What I meant that you could make a tank with 187 #4-6 hull, but 188 turret and filling. But 187 hull have better protection and allow better upgrade capability.
BTW, 187 $4-6 was supposed use X engine, and what tank currently uses it? You guessed right, T-14. So if they went with 187 #4-6 hull, now they could install T-14 in 187 hull and have 1200+ hp. And increased commonality, thus decreasing logistics footprint.