Revisionism is pretending that three conversations of an optional character made a great character development.
Of course, Wallace had many character traits, like being a loyal warrior who loves to fight and ...
Being bald counts as a personality?
Honestly, supports have only improved, but it's fine to acknowledge the weaknesses of each era's Supports system & how they've been improved in Three Houses.
GBA had some interesting supports, but you were limited in that you could only support 5 times with each character in the game. You did feel more invested in them though, because you could only reach A-Rank support with 1 other character & you had to spend time near each other in battle to raise the points. Supports ranged from lost siblings reuniting, people's dark pasts, mild romance, or people just goofing around, but largely they fit the character's & games tone/personality.
By contrast, Awakening let's you support with pretty much every other character in the cast repeatedly without limitations. However, because of the nature of the game, the support conversations were railroaded towards a relationship (this generally applies to Fates as well). This was a turn-off for many people, as they could get old quick. But the huge increase in options, as well as not having to replay the game over & over again to experience all the support conversations was a welcome change.
The issue with both the Pre-3DS & 3DS era games is that most characters only have a few characters they have quality support options with, and the rest of are just kind of fluff, and rarely memorable. Just like you can say for Wallace that being a bald general isn't a personality, I can say I don't remember a thing about Gaius other than he likes candy. Characters have been & will always probably be, somewhat tropey (FE indluges in their own tropes like the Red & Green Knights). I will say that supports in Echoes are pretty good, but the smaller & tighter cast of characters will help with that.
I think it's most important to just be happy that Three Houses gave us the ability to support between most of our units & quality ones at that. Characters have reasonably deep backstories fleshed out in supports, with the occasional humor depending on the pairing. Overall they fit the tone of this game way better than the 3DS entries did with theirs, and with way more substance than any of the previous games. Overall I am just happy where we ended up.