I think it's kinda stupid that they just got rid of the other forestry machines. Keeping both them AND the multiblock structures would've been just fine.
The reason the old farms got phased out is the fact that as the first code of Forestry that was ever written, it was quickly becoming unmaintainable. With every feature added to forestry, with every Minecraft update, it got worse, caused more bugs, took more time to port and even maintain standard operation. It crippled the entire mod's ability to update and evolve.
So no, it would not have been "just fine".
Also, the multifarms are flat-out better in all aspects except up-front cost (and even then you could argue in some cases, since you no longer need diamonds for a tree farm, and one single multiblock is capable of all possible product types). I'm still not sure what makes people so hidebound as to irrationally hold on to inferior machines...