I have had bad experiences with the Evod tank (Not personally, but my gf brother has one and has nothing but problems), If the right amount of wick and the right coil is not used it will leak everywhere. I would maybe look into a kanger mini protank, I personally owned one and had no problems with it leaking or anything.
Another thing the airflow is not good at all, for some reason the bottom part that screws into an ego connection is too short and when its screwed down it blocks the airflow (BTW he has all airholes drilled to 5/16, and still hits like a un-drilled CE4).
Unless you like constricted airflow, I personally have my RDA drilled to 7/64.
What you're saying applies to pretty much all clearos. Sorry to hear that your gf bro has issues, but it's not fair to judge them all by one bad apple.
I have several Evods, T3S, PT, PT mini, etc, and have only ever had problems with one - drilled too low, as you mention. But only chokes off on one of my batteries, and a 510 to ego adapter lets it work there as well.
Many of the bottom coils devices have a tendency to loosen the head when opening them to fill. Always check for that before putting back together. And, when the coil starts to gunk up, we have a tendency to draw harder, since it's not doing its job as well. That can pull excess liquid up the air tube, leading to leaks. It's often normal wear and tear, and user action, that makes them less than optimal.
Draw is a purely personal preference. Some think the PT line are too airy, some like them just fine, and it seems you feel they're too tight. Not a problem, but a choice each of us can make.