You've already got a .25-06 and a .30-06. So, I'd say the .270 Win. would be a bit redundant, unless you're just wanting to fill out the family of '06 based cartridges.

I'm not a big fan of magnums because I'm a little bit recoil sensitive, and you're right, in a 6.5 pound rifle, I'd imagine it'll kick a bit. If it was me, I'd get that Tikka in 7mm-08.