I agree with almost all your points but the 10 man raiding hurting 25 man and raiding overall. What hurt raiding overall 10 and 25 was the one lockout for raiding they started in cata. In wotlk my guild was a 25 man raiding team and we would pug 10 mans all the time when not running guild raids. When that was taken away in cata and one could only raid once either 25 man or 10 man pugging on my realm died overnight. People couldn't pug or they would be locked out from guild raids. Without pugging that is where the community started to die not lfg. I found many of friends and new guildies thru pugging in wotlk and before. The seperate raid lock outs is what killed the communities. People could only raid in guilds and thus meeting new people stopped or serverly halted. With the new raid lock system it is starting to come back. But some of the most fun I had were gold for gear runs where if one had they good they got the gear and then at end the raid split the gold made from the run. You could get gear and gold. And met a lot of people doing those. The single raid lockout was single handily the biggest mistake the game has ever made.
It was blizz listening to a minority whining they had to raid both.