True, and I plan on building out my arena from time to time. But having good players is more important in my opinion. Besides winning, I know I can sell off parts whenever I'm financially pinched. And, in response to the poster's question, a 7000+ arena is plenty big enough for DV and DIV from my experience. Next season will be interesting for me as I won't have the promotion bonus and I'm running a break even economy.
I wish it really was "cheap" when it comes to buying decent PG/SG's.
But training bigmen is sooooooo much easier.