Trends in the Mario RPGs?

All the M&L RPGs have Jump and Hammer as the basic skills and some form of combo attacks.
All the M&L RPGs from PiT onwards have a gimmick.

(A bad one coming in, brace yourselves xD)

All the M&L RPGs have a boss that's disproportionately (do I spell this allright? xD I'm Dutch) diffcult and/or annoying. For SSS, it was Trunkle. For PiT, it was Sunnycide (at least for me) and Bowser+Baby Bowser teamup (ironically enough never had trouble with Princess Shroob or the Elder Princess Shroob), for BiS it was the Fawful Express and DT had a fair share of them for me; Big Massif and his lackeys, the Elite Trio and (UUUGHH) the Somnom Woods guardian robot boss.

(Some more good ones)

All the M&L RPGs somehow reference the earlier games.
All the M&L RPGs have Bowser becoming more and more dangerous on a sliding scale. I'm curious how it'll end up in Paper Jam (tbh I hope he'll become an anti hero sorta and help Mario out then backstab and try to destroy him).
All the M&L RPGs have some unusual situation (as in, something that almost never happened before in a Mario game) happening. In SSS, it's Bowser's amnesia, in PiT it's the time travel thing, in BiS it's, well... the Bowser's Inside Story, and in DT it's the weird stuff happening in Luigi's dreams.