I've got a couple of 6.5s, Wife's RPR and a light weight Ruger American Predator. Been playing with them this last year and yes they are every bit as good as people say.
Having said that, I have to be honest. You mentioned the 7-08 and 243. Both are accurate rounds, both would be excellent deer cart. The 7-08 might be a bit heavy for my taste.
You're 243 is just as good and everything else being equal, just as accurate as the 6.5 CM.
The 243 is actually flatter shooting. My wife's 243, using 100 gr. Horn. BTSPs drop 70 inches at 600 yards. My 143 Gr. Horn. drops 79 inches at 600 yards. The heavier 143 CM drifts 20 inches in a full value 10 MPH wind, the 243, 27 inches.
Those drop and drift numbers don't mean much at the 200 yards you mentions.
The real advantage of the 6.5 over the 243 is when you move to elk size animals, but then, you 7-08 which would cover that.
Don't let anyone tell you the 243 is not heavy enough for deer at ranges.
Day before yesterday, wife got this little guy at 565 yards with the 243 load listed above.
Any excuse to buy another rifle is a good excuse.
But do you NEED another rifle? Slaves get what they NEED, freemen get what the WANT.