First, this is by design. Second, seriously, how fast are you reading scopes?
When I tap into something like on_modified and/or on_selection (which will literally run on every keypress and every cursor move), I make sure to check if multiple requests are coming in too fast (doing a lot of quick typing). That way, I can hold off on executing the payload until constant requests slow down or finish coming in (stop typing). Basically, I have given everyone a respectful plugin that won't bog down when people are doing a lot of typing or holding down the arrow key for cursor navigation (python isn't nearly as fast as native C). I personally think the current delay is fine and have felt no reason to tweak it.
Granted ScopeAlways does very little except post the scope in the status bar, so it isn't going to impact performance much, nor will ScopeHunter if you turn off most of the other stuff, but it can also do much more as well. I wrote ScopeHunter first, and foremost, for myself. I'm not going to try and convince anyone to use my plugin, so if another plugin works better for you, please use that one instead. I personally like ScopeHunter and found it useful when writing language syntaxes and other various things, which is why I still support it .