I wouldn't get my hopes up for a very high market cap around launch time. It's new unproven code. No major exchange will be able to support it in the first few weeks / months (look at the difficulties NXT had). No peer reviews. This will be an infant, just as Nxt was (and still is).

I hope of course that it will launch at a fair price and will gradually rise. A sudden high price can only result in a major dump, but than again: that's very unlikely to happen as there are no major exchanges where you can exchange eXo.