Losing Block is a huge blow. I had to contend with losing X last season (he was our demo - and was the star player on that team), and it took me a long while to find an adequate replacement. It ultimately hurt our ending record as we didn't establish an identity as a more balanced team until midseason in S13.
As for the the future of this team, it will hinge on who they pick up to replace Block. If they can find a mid/high open demo, then I'd peg them for 11-12 wins next year. If they don't, then I think it's a mid-table finish.
The attitudes on this team are all quite good - so that's not an issue. The only speedbump that I see with the current five you have is that they're all going to have to step it up - they cannot hide in Block's shadow anymore and must become leading reasons as to why this team will win in S14. It's a huge task, but it's been done before and I think that this current group of people can pull it off.
Here's a +1 from me. I can only recommend this team as Tery has the "leadership" gene that will be needed to advance the team further.