They had a functioning replay system on the PBE forever ago, that they removed because of reasons. It popped back up again with the 3.14 patch on there now, months later. Again, this is almost surely due to engine/platform/code issues. More than likely, how to not implode old replays every time a new patch hits (which is typically what breaks lolreplay for a while too).
It would be nice to know the breakdown of those employees. A lot surely work in event/PR capacity considering Riots heavy involvement in their own esport scene. Lots of people that just sit around and maintain the servers/DB, which is fine. An art team that really needs a revamp (So much splash art seems to get reworked by people on Reddit then later fixed or redone by Riot). Animators, 3d artists, the people who can actually code in abilities, lore people, coffee fetchers, more random PR people, player support, technical support, etc. I know all chew up a lot of resources. But even skins are getting released seemingly slower than they should be. Community poops out neat skin ideas daily, some of which get made into custom skins in a matter of weeks (new particles and all) by some random high school or college kid that's bored. Meanwhile we get meh visual updates THAT NERFED MY STEEL LEGION GAREN SKIN GODDAMNIT and like 1 new skin a month. It took Zyra how long to have a second skin? Vi? Zac? Zed? What about Steel Legion Xin/J4/Galio? What about more Battlecast? They have awesome established themes to build on, people giving them great ideas FOR FREE every day (bee keeper singed! I mean come on that's good), that literally build on existing assets.
Obviously the more technical problems are a priority and what I care about more, but it again raises the question... why is everything Riot does so slow?