Nobody would be against a dominant DT, but it's also one of the easiest positions to get by with a JAG.
Yes, a dominant DT can change the game (and gameplan), but how many of them are out there? Can you find one on Amazon? The good ones are not available very often. When's the last time the likes of Donald, Chris Jones, Vea, Wilfork, etc. was available in FA? Even Fletcher Cox, who is past his prime, wasn't made available this offseason. Who was the marquee guy this offseason? DreMont Jones? Hargrave? That's $17M-$21M a year. Too high for a RB, too high for a safety, and too high for a DT who isn't Donald/Jones.