yeah, if you're not trying to replicate design blunders like the 99/4a you can probably do a lot better; the mup21 showed that if you're making an asic and willing to depart radically from the conventional wisdom you can get a crtc and a one-clock-per-instruction† 20-bit cpu with a pretty high clock speed into 7000 transistors, less than a z80
in the crtc design space i think there's significant unexplored territory around polynomial interpolation that could allow you to get by with a lot less memory than you need for a whole framebuffer. but it'll probably stay unexplored because it's nowadays a lot more practical to just whack a up5k or something in there, and that has plenty of memory
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†offer not valid for addition instructions, additional stack manipulation fees may apply, multipliers sold separately, your mileage may vary
I have been thinking about display controllers for a while. In the 8-bit age home micros (like the C-64, TRS-80 Color Computer, Atari 400, TI-99/4A) usually had an ASIC display controller.
Some people have built sequels of those computers using DIP chip electronics, such as
https://www.commanderx16.com/
and get frustrated because a decent framebuffer takes a lot of parts: there is an ad in Byte magazine from 1979 or so that shows a color framebuffer for an S-100 machine that is almost as large as my 4080 in area and packed with chips on both sides. It's not hard to design such a thing out of latches and counters and comparators but it is a lot of parts that need to be repeated across rather wide data paths. It's expensive for a product so they wind up making a display controller based on an FPGA or a microprocessor instead, if and when they do get to the point of making an ASIC it will be to put almost the whole computer on one.