I really wish people would drop the whole killstealing thing. Many champions, especially stealthers, are very soft but designed with high damage bursts that can't easily be dodged or anticipated. These would be OP if they could kill anyone without warning, so they only do a healthy fraction of a champion's HP. Additionally, these moves tend to be good at catching runners. If you use them up-front, the only person they're going to be effective on is someone being swarmed who is likely to die anyway, and then you've wasted your kill move, because they'll just go back. If you wait until someone is low, you can clean up a secure kill.
The other day someone told me that RIOT wouldn't design a champion who relied entirely on the principle of kill-stealing (Twitch). Yes they would. (For anyone who doesn't know, Twitch is soft with huge damage burst, so the best way to play him is to do nothing and stealth until your combo will kill the enemy - this baits the enemy into thinking he can get a kill, until it's too late for him to run. At lower ranks, playing him properly will make people rage their faces off at you, because the only way to bait the enemy is to make it look like your ally is going to die by hiding there, and because he can't help much if the enemy isn't getting low, so you just let the ally die and stay stealthed.) Kill-stealing is not a bad thing as long as you're not wasting things that will need to be cooled down ASAP. In fact, in some cases it's a tangible benefit. The best phrase I ever heard regarding the subject was, "ks = kill securing". The idea that killstealing is a problem is mostly driven by personal vanity without regard to the team's victory - they would rather have a 50% chance at a 95% kill than a 10% chance at a 100% kill. More telling, in my opinion, is that people almost never complain about KS at my rank, and then when I had a huge losing streak 2 weeks ago, people were doing it all the time until I won some of my rating back.
