If SU becomes a place where coaches can win and advance their careers, you can get good HC candidates. This boils down to support from the administration and the opportunity to find success. A rising HC wants to go to a place where they have the tools to win and draw the attention of bigger college programs or the NFL. Tuberville broke the mold, but that's what Cincy had going for them -Dantonio, Kelly, and Jones.
The Dome isn't a negative (attendance might be) because as others have clearly stated, it would allow an offensive coach ideal conditions. You have to invest in other areas which would have a greater impact on the program. The IPF is a good start, but it needs to continue to other areas. Recruits who will win games for you are not looking at uniforms, they want a place where they can develop into a NFL player. That means coaches and support staff who prepare them, and who do the things that get you noticed by NFL teams.
Investments in these areas, along with better marketing and promotion to fill the Dome, are all better uses of money than building a brand-new stadium, or paying one guy more money.