IMO the idea Thompson passes up players (whether they play offense or defense) he has rated higher in favor of unknown players in order to boost his ego is foolish on its face. It reminds me of the specious allegation Thompson wanted Favre gone because of Thompson's massive ego.
Thompson has conducted 7 drafts and selected 68 players yet you mention just one player he has drafted. That and your opinion that with the exception of Rodgers, he's "never drafted a marquee offensive skill position in the first round" is the only "evidence" you provide. Because your theory seems to center on the first round, the idea of "unknown" players is somewhat odd. Was there a player Thompson selected in the first round that you hadn't heard of?
Let's look at the evidence: Whether or not you view OT as a skill position it is certainly an impact position that is frequently targeted by NFL teams in the first round and rightly so. In addition to Rodgers, the ultimate marquee offensive skill position player, Thompson has taken two OTs in the first round. In 2008 the first player he selected was Jordy Nelson. Of course he was taken four spots into the second round as Thompson traded down 6 spots out of #30. A reasonable argument could be made that if Thompson wasn't able to trade out of the first round he would have selected Nelson. Whether you believe that or not, the fact remains in four of seven drafts the first player Thompson has selected plays offense.
Expanding a little beyond the first round, here's a look at the players on offense selected in the first two rounds of Thompson's Packers drafts: In 2005 he selected a QB in the first and a WR in the second round. In 2006 he selected a T/G (who ended up playing OG) and a WR in the second round. In 2007 he selected a RB in the second round. In 2008 he selected a WR and QB in the second round (as already mentioned, he traded out of round one). In 2009 he traded out of both the second and third rounds (and he had an extra third rounder) to pick two defenders for the new D scheme Capers was putting in place. In 2010 he selected an OT in the first round. In 2011 he selected an OT in the first round and a WR in the second round. So in seven drafts Thompson has exercised 17 picks in rounds one and two. 10 of those players play(ed) on offense. So in the first two rounds of the draft, Thompson has selected more players on offense than defense.
In order to prove your theory, you would have to present evidence that there was a player who plays offense that Thompson knew would become a marquee player (or at least had rated higher) on offense and he passed him up for an unknown player. Without having knowledge of the Packers' draft board that's very difficult to do. Not only have you failed to do so, you haven't offered a single possibility of that happening. In fact, IMO you have offered no evidence whatever.
BTW, I expect the top of this draft to emphasize defense so I expect the "unbalance" of picking more players on offense in the first two rounds to come into greater balance. But that will have nothing to do with Thompson's ego.