The Elfball league rules seem to allow for some interesting challenges when it comes to team management, which I guess is going to make some decisions very difficult

At this stage (having no experience) I'm just throwing my thoughts out here, but please feel free to comment if you want

Experience versus Bench Depth is the biggest issue from what I can see. As your players improve and become more expensive, you have to lose either reserves or support items to keep to the points cap. My initial thoughts are that this will lead to 2 routes of develpment for your team - Up Front or Long Haul loading
Up Front - Once you start gaining experience, I can imagine that some teams (like Night Elves & Black Widows) could get good mileage out of keeping the bench and support staff more lean and loading players with more abilities? This strategy would rely on them all-out scoring and avoiding attrition, so abilities to capitalise on ball stealing and positioning to score would be helpful.
Long Haul - I could also see some teams going the other way too, where you try to caplialise on the opponent's shorter bench and where your team becomes more powerful into the 2nd and 3rd tests of the game as attrition impacts things. Maybe Dwarves and Deadlings would be good this way? To do this you could chose to not improve rookie players when they get enough experience points, maybe having abilities limited to a few key players and allowing the other team mates to be ready to improve if the key player is injured.
I guess a lot of teams could be managed in either of these directions, or can easliy just find some middle ground?
I love the idea that if you are unlucky and lose several players in a game, this doesn't hamstring your competitiveness for future matches. This is a big plus for me just after starting Orcs in Bloodbowl and having 2 blitzers die in my first game!

I also imagine that the team's roster is going to be chopping and changing a lot between every game, as you manage your preferred Players/Abilities/Support balance to fit within the cap
Looking forward to testing some of this out first hand this week!
Cheers,
Spiky