Adding my 2 cents on the pro-Angell side. I enjoyed her from her very first scene when she more than held her own against Danny, Flack & Hawkes. Someone said something about giving them a "look worthy of Stella"...that's it, exactly! Yet she's not a carbon copy of Stella, Aiden or anyone else. I like that they showed her having some very realistic rookie jitters (your very first Mummy would, after all, take a moment or two of getting used to), and of course her not seeing the trip wire, but these scenes were not at the expense of her professionalism, I've never gotten the impression of her struggling, or not fitting in well with the team. (Quite the opposite, in fact).
I'm not saying I think Angell needs to be more fleshed out into a regular character; I think we have more than enough of those, all of whom we fans would like to see get adequate screen time. But as a semi-recurring character, I think she fits the bill just fine.