I think Riot is a great company. I have never worked at a company that encourages player interaction more. We also try to interact with players in meaningful ways. We have open discussions with the community (when the thread has an appropriately constructive tone).
I read dozens of threads every day, and I cannot reply to all of them. Usually it's because I have nothing to contribute to the topic. Sometimes it's because I am in the wrong department to affect that. There are also times when I read a good idea, but I cannot post about it because of non disclosure agreements. Posting about some things may create the false sense that a change is very imminent, when for various reasons it may take time for things to get to the players.
While I am not involved with game balancing, I can assure you that buffs and nerfs are never "random". We have a team of very skilled players and analysts that take many things into consideration when balancing the game. I hope you appreciate what a complex task it is to balance over 100 champions plus items.
In any case, I hope you are enjoying playing the game. I think the best reason to buy skins is because the skin makes you happy. We don't try to make money, we try to create things that players value, and players can reward us by posting about them, telling their friends what they think is cool, playing the game and being a constructive and helpful player, and sometimes even spending some RP on things.. But really, the primary focus is creating value for you as a player. If we create something that you do not find valuable, then we will try to lean better what players want and create something better next time.
If you are wondering about how Riot treats its employees, I can say that I am treated well.
Remember, spending RP is just 1 way you can thank us for doing a good job. I'm happy if you are enjoying yourself and being a nice person in game. If you give tips to other players that's even better! And if you think we're doing a bad job, just make a polite post about it and we'll read it and try to do better (even if we don't post a reply).