Firstly, i play mostly dota, hence i know every nook an cranny about the game.
And boooooy you are so wrong on so many levels.
Last time i checked, Valve wasn't a charity either, they still manage to deliver on all what Riot promises, because the populace demands it, and all without asking for a single penny from their players, unless they really want to spend that cash.
Just to put it in perspective, Valve currently has ~330 employees of which an amazing ~30 actually actively work on dota.
Sanboxmode:
Been in dota since day one, literally with anything you want and bots for your team, the opponent team, your grandma and your friendly neighbour, with resets on abilities, wtf mode and whatnot. And i can tell you that even more than half of the active populace even of higher ranked players (that's platinum equivalent and above) don't fing use it unless they just want to troll without ruining it for actual people. Those that use it, practice it for their own mechanical training and interactions they feel insecure with, or just use it to try out changes from patches without just jumping into a game, some use it to check itembuild interactions aswell. And guess what, nobody ever fing expects it. I have in my 5k hrs of dota not encountered a single person that ever requested someone who was screwing up, to try it in the sandbox mode, so that's complete bull** just by experience. And you know what that bad wolf Sandbox mode is the actual best thing in the world for? Figuring out where the hell a bug is coming from, and actually finding the string of actions that lead to it. Bug Fixing in dota even of huge, major gamebraking bugs, takes not more than a few hours during Seattle offhours.
Replays:
Another thing there from forever and being constantly improved. Replays were possible when heroes were added 2 at a time with a spectator mode that had instant replays to jump in and replay moments from competitive games yourself, live rewinds, selection of cameraperspective, casters, directed, your own, hell you call it. And all of that was developed while organizing tournaments, balancing and adding heroes to the game. We are not even gonna talk about that poor excuse for a spectator mode that we have in League.
Client:
I'm amazed that League still uses Adobe Air. Btw dota had multiple client revamps during beta, with major changes and they managed to make a completely new client after that aswell that introduced customgames (communitymade, Valvemade, made by your granny, you get the gist) all done from scratch during the still basic development of the game. But Adobe Air is gonna disappear sometime in 2016,maybe or not, the makeover might suffer the same fate as Sandbox, considering Riot's history of delivering....
The ONLY, literally the ONLY reason Riot isn't doing those things? You can't milk the player with them for the highest possible amount of money. It's the only reason, whatever excuse they pull out of their backside, beautifully written by their PR-Office for sure, is just bull***. Why make a communitydemanded feature that is absolutely necessary in a competitive game, when you can't make money off it? Chromas are waaaaay more important, wouldn't you agree?
I have to hand to Riot that they don't outsource their skins like Valve does (once again almost 90% communitycontribution, with some of them making a living off it), but seriously they have more than 3 times the employees, i think you might find a team of 30 in there that can actually do that stuff. And the quality of the skins, boy you should see some of the most recent once (source 2 really delivers, holy cow).
Why do you think dota players spend so much money that 25% off a, crowdfunded Pricepool is 18.4 mill (Valve pocketed the other 75%)? Because the company builds a trust based relationship with the customer. We don't get screwed over, we get the game for free (except our soul) and occasionally we get randomly tossed a free skin (yes even those 50$ ones) and you know what happens? You feel like you should spend cash on that game that has given you countless hours of fun and joy with your friends and strangers, so you can support the company that makes it. This is F2P my friend, done at its finest.
What Riot posted? Excuses, and very poor ones, since they can always just look over at their competitors that shovel that money aswell and take some good hints from them that have proven to work perfectly.