For the first part I would say yes, Jack has done absolutely nothing to make me think he is worth any more money then Stuart Carswell who, if i remember right moved for bugger all. Jack seems to be a smaller, more immature version of Keith Lasley, he has no physic, no ambition to create or have a shot on target and can't really tackle (let's face it, would you put your money on him breaking up an attack?).
I wouldn't say that they have to be "world beaters" just simply have a basic understanding of the game and a good level of fitness/ability. Two things I would say jack does not seem to have compared to a Liam Grimshaw (who has sealed himself a quality move to Preston). Does Chris Cadden have those attributes, I doubt it but let's see...maybe the manager can bring I. Some other starlet. That's all part of the fun of being a Motherwell fan.