I think it really sucks not getting up the order to bat if you do well or go down if you do bad. And choosing players in the team after becoming captain. Playing with same players is just boring sometimes. They don't even change themselves.
Except that going up and down the order based on form isn't really how cricket works. An opener is (generally) an opener long before they hit the county/state/provincial level. The skill set is actually different from that required of a (say) number 5.
I would like it if the career mode was deeper - players retiring, new players coming in, having a lower level than county cricket to get dropped to if you don't perform (and by extension, being dropped or promoted if you're not performing), getting a chance at a higher level because of injury and so-on.
I'm not sure about getting to choose the team as captain (because, again, the captain doesn't usually get to pick the playing 11 on his own, does he), but I can see where that could be very useful - particularly in situations where my boy is batting at the same slot as someone I still want in the team. I guess I wouldn't want that one restricted to just the captain, though.
It would also be good if the "getting dropped/promoted" thing happened to other players as well.
These things, however, are very very tricky to get right. The game I play with a deep career mode (MLB: The Show) often has issues because of this kind of stuff that they have to patch - and it's the kind of stuff that's a significant cause of player complaint.
In particular in MLB, they have had issues with how long it takes for a players career player to get to the Bigs - so by the time he gets there, the established players have moved on.
A similar problem could occur here for the people who start at 16 (after patch 2) - so then the complaints become "I wanted to play my cricket with *insert favourite player here*, and they've retired/got dropped/been caught in a fixing scandal (choose one) before I got there."
I guess what I'm saying is I'd like to see all that stuff, but I'd also like the foundation of the game to be rock-solid first