I find that most of the Williams games have wizard modes that are achievable. Although that doesn't necessarily mean that they are fun to play. I can't think of any Williams game that has an unachievable wizard.
Of the Stern games, I'd say that T3 has probably the easiest wizard mode to achieve. IM, Jericho and Do or Die are not too far out of reach - as opposed to Do or Die Multiball.
The rest require too much for an 'average' player to get to wizard mode on anything like a regular basis.
I would say I am a good player, and have completed, or got to, the majority of Wizard modes for games I have owned - including Valinor(Lotr), Superhero(SM), Encore(ACDC), Final Battle(Avatar), End of Line(Met).
As for people saying that Tron or PotC have easy wizard modes, you're either playing a game set up WAY too easy, or you're just trying to make yourself seem better than you are. I have got to Portal once(despite getting to Sea of Simulation on a regular basis), never got to Gauntlet (despite getting to 4 winds numerous times) these are NOT easy wizard modes at all.