That's a bit much, though. Joints in the shoulders needs to be accommodated by both central robot and attaching piece, and many transformations can't make that compromise without ruining the aesthetic of the arm's vehicle.
Same goes for hips, which would almost always need to be ratcheted because of the weight they need to support (Blah blah cheap BoA plastic is light, yes, but it can still get cumbersome).

I don't need bicep swivels and an ab crunch is a pipe dream, but neck swivel, elbows, and maybe knees if I'm feeling fancy, would be all that I would want, right now.

I can take a sacrificed aesthetic for the individual zords, for a fully articulated Megazord.

But that just leads to the question of why have the DX mecha make the aesthetic and visual sacrifices when things like SRC drops the combination all together for an articulated Megazord?

I don't see this ever happening. The design philosophy behind mech/zord toys isn't about articulated robots, it's about the combination gimmick. The toys need to be able to have separate modes, a combined mode, combined modes with later releases, and sometimes alternate solo modes. All the engineering goes into that and articulation is typically the first thing on the chopping block to accommodate the combining. Unless Sentai goes back to mecha that are either standalone or formed out of 2-3 components, I don't see articulation ever getting much better than 2-5 points on average.

It's because I'd like something that combines too.

But at the end result you'd have something like Hybrid Style Convoy. Making so many sacrifices for the robot mode that the alternate is just hideous.

How is it that a recent combiner from Transformers (official or fan-made) can be articulated and good looking in all modes? Candy toy Sentai Robos are more articulated than DX and also accurate (hit or miss on that, but even DX toys are or at least feel inaccurate in proportions) to the show.
BoA is stuck making new molds, and if Samurai is anything to go by, they don't care if your TigerZord doesn't drill things properly or your BeetleZord is a sheild.
Besides, ZordBuilder is (possibly) doomed by Go-Buster and Kyoryuger.

I can't vouch for the fan-made stuff, but Hasbro combiners always have to sacrifice something for their articulation. Usually it's stability or compromised aesthetics. None of the modern Hasbro combiners feel quite as solid and durable as the Bandai Super Sentai ones. It's no wonder people still prefer G1 combiners over the stuff we get nowadays.

I do think we'll see the end of the Zord Builder come GoBuster's adaptation...

At least Hasbro tries. Execution might not be pitch perfect, but "A" for effort.

Look at galleries of the GoBuster mecha and try to place the Zord Builder pegs without completely compromising everything. It's fairly hard.

And Kyoryujin's legs can't work with the Zord Bulder pegs either. The shoulders maybe, but those pegs would be under a LOT of stress.