Nah, that's not what I get when I think of a tweener. Offensive roles are very versatile and all types of players can be successful in the league. You can have a rolling player or a popping player, you can have have a high post hub players, you can have stretch players or playmaking players, you can have offensive creators, etc and every combination of all of those and more. If you don't have low post presence or ballskills for the perimeter, that doesn't make you a tweener... that makes you a limited offensive player. Hell... do you know that we have such a player starting for us right now? He's arguably a top 15 player in the league and all-NBA 2nd team last year. Yah. Gobert cannot post up(even if he has size) and he cannot handle or shoot. That doesn't make him a tweener.
Tweeners to me is a description of defensive inbetweeners syndrome. A player who cannot guard any position.