Wallace was a 4X DPoY, one of the best defenders/rebounders ever, and went toe to toe with Shaq in a Finals that his team won, he's clearly deserving of being in the HoF even if he was basically a 0 offensively.
Mark Eaton was an elite shot blocker (all time leader in blocks per game), led the league 4 times and came close several other times. He was two time DPOY. And a very good rebounder.
And like Wallace, Eaton was basically a zero offensively.
Should they put Eaton in?
Gobert has won DPOY twice now, and I don't think he should be a HOFer.
Marcus Camby, Meta World Peace, Tyson Chandler, Joakim Noah, and Marc Gasol all have won DPOY.
All good, useful players. (And honestly most of them were much better offensively than Wallace.)
But HOF? I just don't think DPOY is enough, even with four. It's part of the consideration but I feel like you want at least competency in the rest of a player's game.
Rodman is the only close comp I see. But while Wallace was a very good rebounder, Rodman was such an incredible rebounder it was ridiculous. Wallace wasn't quite that (Rodman is 12th all time in rebounds/game, Wallace is 75th). Rodman's argument was unique to Rodman.
If we go back to baseball for a second, Ozzie Smith is in the HOF basically because of his elite defense, maybe the best of all time at ss. But he also hit .262. He wasn't an elite hitter by any stretch but he was at least ok. Had he hit .162 instead, I don't think he's a HOFer, and I don't care how good his defense was. That's Wallace. He was a .162 hitter.