Well, I don't really see you should be getting GIS if you have a million in a TFSA OR a mil in your home. OAS less so, but still somewhat. CPP of course no impact.
There needs to be some kind of asset test/means test for the TFSA, at least by the time I get to OAS age - which is ~30 years, even at 5.5k a year it should have become $300k invested in that time, probably more. At $10k, it'll be much much more.
Now of course the counter is always that you're penalising people who save/invest vs those who spend it all, but whatever, I'm a big boy, I'm going to retire early, and I'm "rich" (not really but compared to norms who have car payments...), so I don't feel it'd be fair to get GIS.
Of course, when I DO get to that age and am eligible, or not, I might feel different.