Crow - There is an old adage that states "Be careful of the man with only one rifle - He probably knows how to use it." Your .270 is capable of taking deer and coyotes anywhere from point blank to "way out there".
But with that being said - There is absolutely no reason for you to need an excuse to get a new rifle. Maybe something smaller like the .243. For your purposes, I don't see the need for anything more potent than the .270. EXCEPT a fun gun like a 45-70 of something along those lines - you know, a fun gun. Or maybe a fast handling saddle gun like a Marlin 336, 1894, 1895 or Winchester 94 (A close copy now made by Mossberg)