We can't screw with the rules for no good reason beyond lessening the impact of a plane.
My reason for adding it are as follows:
1) We have a 262, and a 163 (the latter saw less use than the B-29 by far), so we're taken care of for interceptors (if you really feel threatened by the B-29, you can up a 163, use 1/4 fuel to climb/accelerate to a good gliding level, and glide to the forward bases)
2) We have the Ta-152 and P-47M/N for when they're super high (30K +) and away from the 163 enabled bases.
3) Just about every other fighter we have can deal with them when low (even the P-40B provided its packing some alt and speed).
4) You're all paranoid, thinking that if its perked at 400 or so, there will be way more than there are 262's. The tiger is perked at less than 50 usually, and yet you see relatively few of them comared to M4's and T-34/85's. Another example is the Tempest, perked relatively low, and yet there are fewer of them in each tour as opposed to most other rides.
5) You're over estimating its impact on the game as far as its survivability goes. Its still a bomber, and unless someones asleep at the switch, they aren't going to get through.