In my last playing session, I discovered an interesting way that the new late combat joining system could be a problem: if the original player leaves.
I joined a combat in progress so that I entered alone (well, fortunately, my buffaloon pet was there with me). Then, after the first round, the original player left (hit Flee or logged out). Now I'm standing there with no crew and three shark men surrounding me. Thankfully, this was only at level 2, so they didn't hit that hard and I was easily able to dispatch them with the help of my pet, but this could be a problem at later levels. Sure, you can always flee yourself, but then you could potentially end up running quite a ways back to get to where you had been fighting.
Now, in the upper levels, at least at this point in the game's life cycle, I don't see that many other players anyway, so I suppose this isn't a huge deal. Just thought it was worth mentioning. Beware!