yes, please, mint/lib(c) should provide TOS compatibility until FreeMiNT
is the primary OS on majority of Atari machines ;-)
I don't know. Considering the fact most of portable software (this is what we're talking about, right?) depends on filesystem with long names, a lot of memory, fast CPU etc -- how many apps/games would you like to run on anything other than CT60/Aranym? And since there's always "dummy proof" EasyMiNT, everyone is free to install the OS even just for running ported stuff. Not big sacrifice I think.
Plus, let's review the recent mint list issues, which started this discussion -- everything was about gcc, ssh, binutils, coreutils, ... packages. Nothing you'd like to use on TOS.
Other side is native Atari development -- in case I'm programming normal GUI application I'd be certainly happy to have it runnable on plain TOS / older Atari machines. In this case maybe current mintlib would be sufficient (+ the Vincent's work on ELF obj format I'd say perfect).