These champions kits aren't designed to be hyper mobile though. They are supposed to have the inherent weakness of being seen coming, and their lack of risk comes from their base stats being higher. You don't have to risk nearly as much trying to get to your target because you can just heal it all back up in a matter of seconds, where Lee and others trade that sustain for other utilities, like the luxury of ward jumping.
The options can indeed be burdens, because someone that doesn't use them correctly can make mistakes that show the vast difference between a new player to that champion, and one that has 500 games of that same one.
I can't believe I actually have to explain that linear kits are just blatantly less skillful, while non linear kits take time to learn. What part about Lee is so hard to learn that you feel the need to defend other champions. They're supposed to have different strengths and weaknesses, and varying difficulties. Voli takes less time to learn, and this doesn't require a rewarding gameplay. It's an issue in itself, especially considering he's in a state that requires work like a full VGU.
He doesn't make huge decisions the way other mechanical champions do. You just decide who you want to go for, and either do it or don't. No mechanical outplay, no skillshot that's detrimental, no way for the enemy to play against you besides running the opposite direction.
Other champs like Lee need to decided things like positioning a whole lot more because of the way his kit revolves around his ult and Q. Voli just has to be a front liner. Lee needs to use his ult at the right time and right angle. Voli ults whenever he can because there isn't a reason not to. It's a no-brainer. It requires less skill to decide "Yes I do want electric claws, thanks for asking."
TL;DR- Flashy kit or not, mechanics are mechanics. Some champs have them, some don't, and the more they need to juggle, the harder they are.