If stamina is implemented, and if it is implemented anything like I designed it (Can't say as I am not a tester presently), there are going to be more 'delays' filtered into the game, but they shouldn't slow anything down. Some delays just alter gameplay. For example, having a stamina bar that allows you to optionally do something special at the cost of temporary exhaustion. You don't have to use it, but it's there if you want it, and you pay the price for missing somebody with it.
The tele delay was not a bad idea it just wasn't worked out very well, and the idea is improved in 1.3 in that it isn't an ever-present delay, it builds up, so as to still discourage tele scripts (some of them anyway). A delay on the repeat of major attacks like the kame wouldn't be bad, but it might not fix the problem either. Generally it only takes one beam to destroy a quarter of the map when somebody wants to use it that way, and if they're good with them, you're dead and respawning while his delay is disappearing. If you make the delay too long you have to compensate by making the attack have a stronger effect as otherwise if you miss you are forced into melee, and although melee is far more popular, we like the idea that you can do something else if you can't deal with the speeds or have latency issues.
Anyway, like I said, things are going on in 1.3 that should theoretically handle all the issues put forth so far. Only time will tell for certain.