Well, for a superhet you do need front end filtering, but that is not necessarily the case for a direct conversion receiver, not when filtering done at DSP level.
Also, looking at schematics without knowing how they works, b/c the entire Rodinia is "not fully known how it works", is not very useful. Have you actually measured the Receiver Effective Sensitivity of any of those Gen2 TRBO radios? Doesn't sound like you have, by the tone of your statements. And by Receiver Effective Sensitivity I don't mean absolute sensitivity, which is a worthless figure.
The XPR5550e Gen2 measured with an ISOTEE has recorded the best Receiver Effectve Sensitivity of any radio I've tested to date, that includes everything ham, lmr, etc. Nothing dual conversion superhet I own, including my XPR4550 (superhet), nor EVX-5400s mobile (superhets), with pretty decent front ends can touch the XPR5550e radio, in the ISOTEE and in real world performance results.
The XPR7550e UHF can hear crystal clear audio almost half a mile further than any other radio on just 1 W I own, that is including the XPR6550, the EVX-539 mobiles, and everything else UHF I own. Same story applies to VHF...
Sounds like you are just looking for excuses to justify buying another POS Baofeng... good for you.
G.