The problem with using blitz for pattern recognition is that unless you take the time to fully understand all those patterns, you aren't learning the patterns correctly. If you are going to do that, you have defeated the idea of seeing lots of patterns quickly.
I would recommend getting focused sets of tactics and positional patterns and drilling those, learning them thoroughly first, then drilling them on repeat. This seems superior to me since you are seeing lots of patterns, but they are useful patterns and not random ones--additionally, you can learn understand the concepts fully more quickly since they come with instruction or are part of a set drilling a particular idea.
To elaborate on the first point:
Say you play a blitz game, and in the process, you see 5 important positions that would be useful to burn into a "pattern memory." This is generous, but certainly possible.
You spend a few seconds on these positions in the game. If you don't look at those positions again, you are certainly unlikely to understand how to improve your handling of that position in the future, assuming you didn't figure it out during those few seconds of game time (and how would you know that for sure).
So, you're going to have to go back and analyze the game, taking the time to find these positions and analyze them thoroughly anyway. You might as well just use the time to play a higher quality game and try to figure it out at game time anyway, which will help you more.
The idea of rapid-fire blitz pattern recognition seems to be to just play lots of games and learn the patterns superficially, though, which would be sub-optimal. If you don't spend time on these positions at some point, you won't learn them correctly.
Additionally, some of the best lessons a player will learn is the consequences of their mistakes. When they make a positional blunder and have to suffer for an hour and a half because of it, they will remember that positional idea a lot better than if they make that mistakes in a blitz game and the game is over less than minutes later and they're on to a new game.
In a blitz game you do learn patterns correctly though (at least if you're opponent isn't too weak) because you see how the position turned out and whether or not you liked that.
Don't get me wrong, solving tactics and all that is important, possibly more than blitz but that doesn't mean one should ONLY do such tactics and never play blitz.
I don't think that superficial of a look at "learning patterns correctly" will serve a chess player very well at higher levels.
You can use blitz as a tool, but in absolutely no way think it is required or even optimal. Probably the best way to use it would be to get a lot of experience in an opening, but that's really hard to do since your opponents usually won't cooperate.
<The problem with using blitz for pattern recognition is that unless you take the time to fully understand all those patterns, you aren't learning the patterns correctly. If you are going to do that, you have defeated the idea of seeing lots of patterns quickly.>
Exactly. Your brain goes into "auto-pilot" mode and you constantly only see the patterns you've previously encountered. Also, because your opponent has limited time, he or she cannot defend adequately. Hence, from an objective point of view, your attack or plan may likely not work in classical.
What's the difference between a club-caliber player who's been playing for 20 years versus an 18 year old master?
The master's calculations are more purposeful, cleaner and sound. The club player has been relying on the same intuition, artillery and understanding. Hence the rift in their rating.
<Additionally, some of the best lessons a player will learn is the consequences of their mistakes. When they make a positional blunder and have to suffer for an hour and a half because of it, they will remember that positional idea a lot better than if they make that mistakes in a blitz game and the game is over less than minutes later and they're on to a new game.>
Yes. This is the greatest torture I've encountered in a 90 minute OTB game. I am just praying for a blunder or a sequence of sub-optimal moves from my opponent.