It's always difficult when you have players who are honest tryers.
They'll often bust a gut for you in terms of effort, but that still doesn't mean they are long-term solutions.
For me, Powell typifies this. He's a willing workhorse, and Isa is similar. Players like that are vastly preferable to players like Clubb and Flower, who are injured far too often, and especially to players like Tautai and Navarette, who are totally ineffective.
But even then, I don't think you can afford to have more than a couple appear regularly in your first team. Not if you want to compete at the highest level.
You can't beat genuine class.