A couple considerations towards keeping it as a 30-06. First off, there is no such thing as too many rifles in 30-06
And why mess with rechambering when it might be more fun and more effective to look for another rifle in the clambering you want.... Unless you really enjoy redoing guns, then by all means
But my best reasoning is this;
If you would want to shoot 200 or 220 grain bullets you can sight one in for that. And keep the other for 150-165 grain, or the near perfect 180 grain.
A reason for the heavy for caliber bullets would be for example a PG hunt in Limpopo where long range shots are unlikely but you could choose the biggest PG as well as small critters with a heavy slow moving bullet. Such as Remington Core-Lokt 220 grain. Remember the need for bonded bullets in Africa is with the higher speeds we mostly shoot these days causing cup and core bullets to blow up and fail to penetrate. With slower speeds and heavier bullets you should not have those issues. Plus the slower speed should not blow up smaller thinner skinned animals. A fine Ruger Mark II with wood stock and high quality bluing is hard to beat as a low cost but classic looking rifle