I don't view it as a bad thing. Not each creature should survive. Permanents that do survive win the game, and they do that quickly. I appreciate the skill of appearing weak and harmless, so that players don't look at you when they search for targets for their removals. I even more appreciate convincing everyone it's
to their advantage to keep that threat alive, then kill them all with it.
The idea that "a 6/6 with relevant abilities is pretty good" seems incorrect
You should have higher expectations

A 6/6 doesn't get the job done fast enough to be very relevant here. Four turns to kill a player is not realistic. Which is good IMO, it would suck to gaze at a dragon for five turns and not be able to do anything about it while it slowly kills you. Getting only 1-2 hits will not help you in the long run too much as it draws more ire to you from the beaten player. In my stack I just completely ignore attacks from anything in that range of damage. Four turns away from now a removal spell would probably resolve, someone else will mess with that opponent or I would just kill him before that. I wouldn't spend a removal on it even if I have it, in most cases.
Is creature combat a relevant part of Type 4 in your stack?
Usually, the final nail in the coffin, the end result of the masterplan that results in a player dead is an attack from a creature, and it's by far the most common killing method here. Creatures have the advantage that you cannot know who will they attack, so they would often dodge counters. They are political tools. You usually aim to attack someone after he had already spent his spell for the turn, maybe for countering yours, catching him totally by surprise.
Blocks are pretty rare. I would say that a block occurs every second game. It's almost always better to be aggressive here, and we like it that way. Games shouldn't drag forever.
Sometimes the player you wish to attack is just in a too good board position, or his life total is too high compared to his power AND that player considers you as someone neutral or a friend. Then it might be best to keep your creature back, not make an enemy and threaten everyone with your potential to attack them during the next turn. You are standing and watching, waiting for the next opportunity.
That happens somewhat more often (a bit less than once per game). But still, if a player wants to kill you, it's almost always better for him to spend his removal on your creature (often even a few turns before he attacks you) then to leave it alive, even if his creature is able to survive the block. Giving a player a turn to play sorcery speeds in this format is way too good to take the risk.