I share a similar experience as you. Didn't sell at the high, but had a decent ride, and have always kept an intellectual interest in following their progress. As with any business, the bull case would hinge on one's confidence in the management's ability to find profitable opportunities to deploy their capital. The bulk of their earnings still come from the run off business, which continues to be attractive (but they now run it at a lower leverage compared with their earlier years, so ROE is lower today than before even within this line).
A big piece of the forward looking prospect at this stage seem to also hinge on the sponsorship of Goldman and Stone Point (the PE manager of Trident). By all accounts they took a run at Transatlantic Re before losing the deal to Alleghany Corp, which turned out to be a very good deal for Alleghany. I would imagine one of the reasons they lost is that they didn't have a live insurer, and the seller and regulators probably preferred someone who actually runs a live insurer rather than a pure run off operation. That plus the Seabright exercise seem to prompt them to buy Atrium and Torus and get into live insurance. All of this have footprints of Goldman and Stone Point.
So at this stage it's very much an evaluation of the management's ability to continue to find profitable run off opportunities and the sponsorship of Goldman and Stone Point, just like it was really an evaluation of the capabilities the management and the sponsorship at JC Flowers when it was a JC Flowers company.