Lol, maybe. You are right on the 270 not being adecuate for a 700 yd kill, but the 280 AI will do just fine.
Why don't we take a step back and look at actual numbers for a minute. Most factory .280 AI rifles are going to have the best luck with bullets in the 160 grain range, you start running the 175+ VLD style bullets and you're having to compromise on powder room for higher BC bullets in a factory magazine. Same goes with the .270 we're around 150 grains, but those of us who shoot it are also hamstrung by the factory 1:10 twist in these rifles. The .280 AI will always have an advantage with speed as well because of its larger case capacity.
So if we compare some bullets and get some real data you'll find. I computed these using JBM Trajectory,
an average of what people post as actual speeds and what reloading data I could find using these bullets with a 100 yard zero and at sea level. Since 700 yards seems to be your limiting factor lets for the .280 AI let us use that.
.277 145 gr Hornady ELDX MV 3000 fps
@ 700 yards
-14.7 MOA drop
4.6 MOA wind
1883 FPS
1117 Ft-Lbs energy
.277 150gr Nosler LRAB (.278 G7 Litz corrected BC) MV 2900 fps
@ 700 yards
-15.6 MOA drop
4.5 MOA wind
1830 FPS
1115 Ft-Lbs energy
.284 162 gr Hornady ELDX MV 3000 fps
@ 700 yards
-13.9 MOA drop
3.9 MOA wind
1987 FPS
1420 Ft-Lbs energy
.284 175 gr Hornady ELDX MV 2800 fps
@ 700 yards
-15.9 MOA drop
4.0 MOA Wind
1381 Ft-Lbs energy
So when I look at long range cartridges, first thing that concerns me is wind. All of these bullets are within .7 MOA of wind value at 700 yards but that's pretty darn close. Next thing I look at is velocity I like to keep my bullets well above the minimum working velocity, Nosler claims 1300 fps on the LRAB I don't know if Hornady gives a low. However, they're all 1800 fps plus and I think they'll work at those speeds. Drop I don't worry about a laser range finder and a scope with repeatable adjustments will take care of that. I don't care about energy much either, if energy was truly what was needed to kill animals like elk then we wouldn't be allowed a primitive hunting season. However, all of them are under the 1500 ft-lbs most will say is necessary for elk hunting at 700 yards.
So in my reality you're going to go from a .270 Win to a .280 AI for .7 MOA wind, and 157 FPS gain. Again this is just my opinion, but that doesn't make it worth the cost of a rebarrel on any rifle. Especially a Tikka that probably shoots lights out as is, and why I say money is better spent on ammunition and trigger time vs. gunsmith and barrel costs.