-Can't say I'm running into much issues with the rad roaches, they die pretty quickly to any room that is full. If you're end game shuffle all your empty or storage type rooms to the bottom of the vault, you should have plenty of caps to do so. That and take the time to go one by one through the dwellers to establish a minimum standard of weapons for the vault. I'm to the point where I sell off anything less than 12 base damage. Even with that though the rad roach attacks are scaling up, and as they should frankly. The game needs some sort of challenge.
-If you're still trying to fight it out against the raiders in at the vault door room, then you've fallen for the svcker's bet. Early game, Bethesda teases you about establishing guards with your best weapons. When you have an enhanced flamer and 3 raiders come in with 10mm pistols, yeah you can totally get away with it. When 4 of them roll in with plasma rifles a 2 vs 4 is never a good fight to take. As their weapons get better and their numbers increase the best way to fight them is to build 6 man room, I recommend a Nuka Cola plant since the high "Endurance" stat dwellers take damage the best, then its 6 vs 4 and you can stack a lot of decent weapons that you haven't already given to your explorers. I timed a fight with raiders rolling in with all plasma rifles against a room of 6 rusty flamers, from the door dropping to them all being dead was less than 5 seconds, my guys took minimal damage. No balancing required, just adjust your tactics.
-For the population issues I recommend you start skipping all the pregnancy daily quests and just keep a handful of slots open for an legendary in a lunch box to pop on by. But, overall, yes the devs were lazy and figured that they didn't need to to program anything into the quest system that would anolyze whether the quest was even possible for the given vault giving you the option to skip a quest a day. It's a lazy solution, no argument, but it's what they've done.
-Would love to see an overflow market, but honestly I've been at and above max caps for the game for a while, other than working towards unlocking more legendaries or lunch boxes, there is nothing they could offer that is meaningful.
-Yep the game performance svcks pretty hard when you hit max vault size. I can only view my explorers now by opening the gear and sorting by job. To try and open them normally and click through them like is intended crashes within the first 10 or so. It's been that way since I got above 50 explorers.
-3 minutes is plenty of time to click through the vault, even at max size.
-yeah, weapon/outfit sort would be sweet.
-About 2.5-3 days seems to be the sweet spot from my loose observations for finding rare and legendary weapons, but overall it's really very random. The only thing I've had much success with is just sending out an absurd number of explorers. I have 95 out right now, all max stats.
Would love to see more for the end game content as well. Looks like they'll be adding some stuff on the Aug 13th update, but doesn't look like much to enhance the experience for those at max.