This is good for white.
Marshall defense

In the first game 8. e5 seems to provide White plenty of attacking chances against the Black king using the b1-h7 and c1-h6 diagonals.
I'm guessing white must win a lot of games from 9.bxc3. Looks kind of like a Grunfeld where Black might be worse off w/o the DSB. Natural moves like Bd3 and e5 look strong. Maybe even something like g4, h3, Rg1 might be OK. It doesn't look like Black has all that much going, so maybe a more typical Grunfeld center pressure plan is going to be good. Question is what's the most principle'd plan for white?
Opening books pretty much stop the clock at move 4 and say "white is better". Well, OK, white is a little better, but, consequently, the themes and plans aren't much discussed. White gets the classical center (YAY!), but it's a somewhat weak version of this center as one cannot really defend it with pawns, and it can certainly collapse if black puts enough pressure there."
I have had this sort of position quite a lot, always as white. And I am afraid I don't agree with this. If you look at the position Alison gives after white's 9th move, I think white is much better. If white can play 10 B-g5 black will be forced to seriously weaken his kings side to avoid losing a piece, so likely has to play 9... h6, which is a non-developing move.
White can defend his center by moving his N on f3 and playing f3 if needed. The center is good, as are the 2 bishops.
"When I looked at this with an engine (a year or two ago), it kept telling me to push e5 here, but I never liked the positions I got - they often had this stupid looking immobile pawn chain from c3 to e5"
I agree with you on this. White should only play e5 here if there is a strong reason to do so, like winning a piece or gaining an immediate attack. Generally the pawns are better on d4 and e4 than d4 and e5.
It seems you have something against the strong c3-d4-e5 pawn chain. The fact of the matter is that Black's position is clearly worse after e5 since h7 becomes weak (e5 controls f6 and thus the Nf6 can't defend h7) and the Bc8 is impeded by the backwards pawn on e6. Playing b5 would hang the pawn and after b6, Black's pieces become targets. An example:
I get it a lot.....I'd say about 1/3 of my white blitz games and more than a few slow games. Opening books pretty much stop the clock at move 4 and say "white is better". Well, OK, white is a little better, but, consequently, the themes and plans aren't much discussed. White gets the classical center (YAY!), but it's a somewhat weak version of this center as one cannot really defend it with pawns, and it can certainly collapse if black puts enough pressure there.
So let's talk Marshall defense - how are others thinking about these lines? What are some ideas you've encountered? What are the best ways for black to look at the position?