Again it depends on your perspective. memorize 20ish powers (maneuvers) over the life of the game or peruse the diversity. Talk about analysis paralysis.
Yeah, I don't understand what you are getting at here.
The player levels his character, or lets take the worst case scenario, you're making up a brand new level one PC.
The player at level 1 has to choose 2 at-wills out of at most around 8 choices, 1 encounter power out of again about 8 choices, and one daily out of again about 8 choices. Yes those are a fair number of choices, made once each. At each level up there is another similar choice for most levels. The player only needs to study 8 things at a time. Usually several of those choices are easily eliminated.
During play the player needs to choose each round between one of at most about 20 powers and at level 1 the choice is between 4. Again most of those choices are usually eliminated right off the top.
Using the PP system you outline ALL of the 20 choices exist every single round and the decision is more complex because it has to balance using a resource pool of PPs (and the choice to "use" or "burn" each one no less). On top of that the choice is possibly multi-faceted because the player may want to stack multiple effects. Admittedly many of these choices may also be eliminated right off the top, but to be useful the system has to at least allow several choices in any given round and various permutations. It seems hardly likely that the available choices to be made will be much less than what would be needed to select one of a number of powers available to a paragon tier or higher PC using powers.
From the DM's perspective it is not accurate to say that the DM needs to know 1000's of powers. The players will only ACTUALLY have at most 100 or so powers in a worst case scenario at high levels. On top of that the players should have all the powers in play printed on power cards. In practice the DM rarely needs to know the details of any given power until it is used and at that point it is almost always pretty straightforward as long as he has a good grasp of the general rules.
With the PP system its true the DM needs to only know 20 maneuvers, but he also needs to understand all the potential permutations of each of these maneuvers. He's also going to have to come up with rulings as each permutation comes up to determine how they interact with each other, etc. Ideally he should know all of this ahead of time, but we'll imagine that only a fairly small subset comes up in actual play. That still probably means fully understanding 100 or more permutations. Most of them will be simple and unremarkable, but so are most powers.
IMHO the "analysis paralysis" imposed on the player each and every round of play as they try to balance out use of PPs and come up with effective combinations is easily at least as serious as with powers. On top of that the player never really knows for sure how the DM will interpret different combinations and is thus always subject to either second-guessing the DM or else playing 20 questions with the DM where he has to start asking questions with every action to find out if it makes sense for him to do a specific thing.
I think the overall result is going to be a lot of disagreements where the players have a different view of what should work how vs the DM plus a lot of backtracking and questioning. All on top of the initial choosing of an action each round. I can only say my 30+ years of DMing experience doesn't make me confident this is a faster and simpler alternative to powers.
And in the final analysis does it gain you much? Page 42 already exists. Admittedly it is intended to cover "special" actions, but its always a player option to try something. I'm not convinced you're creating a more flexible system by doing away with powers.
I think its something you'll really have to run in a real game for a few levels and decide if it works or not. I suspect you'll find there will be some tweaks you will need and added complexity required to make it workable. It may end up working well for you and I'm not discouraging trying it, but I don't think I could add much in the way of constructive input about the mechanics without running it and truthfully I'm not that enthused about running heavily house-ruled systems. Even if they are marginally better than the base system its always a big hassle getting everyone to go along with it and customizing every new bit of content that comes out so it works with your variant system. Given that 4e works reasonably well it seems like the payout is small at best.