I have a small complaint about it, there seems to be more and more DC's in each game, I remember that it was near impossible for me to not DC in a game a few days after the release of spectator mode.
Other than that, it's fine, I like it.

Spec mode is great and the only complaint I have is, though I understand the current team color scheme, would it be possible to allow the spectator to change the color of the teams one is spectating? Light Blue and Off Purple blend well together and even after watching a match for more than 10 minutes, it can still be difficult to differentiate between team members.

Spectator mode is great, but one thing is bothering me. I don't always want my friends spectating my games.
I have a decent 230 people on my friend list, and at least 30 of them have spectated my games, and harass me while they're spectating me. It makes me feel on edge ._. Its not fun playing some silly games with full premades, then going out the next day with those people bothering me about the 'stupid' matches I played for fun :/

I have two suggestions!
Keep a tally of dragons and barons killed.
For the featured games on the LoL homepage show their summoner skills as little portraits before you enter the game.

Awesome edition! But 2 other complaints. When buying stacked items each time a stack is added the shops screen refreshes and gets choppy and nasty. Also I HATE how you have all chat disabled by default... Make it an option to turn off all chat not force people to turn it on.. Thats a absolutely horrid idea.

Hey guys, came here to say I love spectator mode. I do have one thing I'd love to see but am unsure of how you'd implement it. It'd be great to see some players runes/masteries while they're playing. I know I'm always curious when I see a champ I love doing extra well I want to know how they build them, but I'm really not going to look up their summoner name and dig through their pages... Anyway that's my 2 cents, not really a necessary addition, but one I'd love to see.

Great work guys, keep it up and I'll keep givin you monies.

You should make it possible for people to chat with people in their friends list while they are spectating. By this I mean if I am not currently in a game I should be able to initiate chat with my friend who is spectating a game. That way you can encourage people to spectate while waiting for a friend to finish a game. I don't see a problem with this since there is the time delay in spectated games.

Other than that quite a good job keep up the good work!

Suggestion Regarding Team Pings:
If the pings could be shades of the teams color instead of always the Red Reticle that would help the audience know which team Pinged a target. Reason being that when the audience sees either team ping, currently it is always the Red Reticle and so it is confusing to the audience.

Is Drop In Spectate not allowed in Custom Games?
-Reason I ask is that I have had friends that I wanted to spectate and was not able. For instance a friend of mine was playing an 'ARAM' game and I was unable to Drop In Spectate his game.

Spectator Camera Request: Zoom Out Increase
When spectating it would be nice to be able to zoom the camera out further than normal so that the audience can view a wider than normal range of the playing field. This would provide more tactical information to the audience which would provide for a better 'show'.

I would like to be able to right click one of my friends who is already spectating a game
and spectate the game that he is spectating.