Well played, sir, well played indeed.
Possibly a bit too subtle for some readers, judging by the responses.
@biostem, I'm sure you're a fine upstanding fellow. However, being new to the forums, the only place I've seen you offer a reply to someone asking if there's a better way to do something, is in this thread:
If your replies there are typical of your "tactful" approach, well, I do not think that word means what you think it means.
Personally I find that mid-mission is an unproductive time to suggest changes to another person's playstyle, unless they've made it clear they're looking for tips and improvement. I'd either ask them if they wanted some tips on getting the most out of their powers, and follow up when appropriate, or maybe send them an email afterwards with some pointers. (Assuming I thought they were educable.)
One thing I've noticed is that coming from the direction of "you're doing OK but could get a lot more benefit from..." is generally better received than starting out with a "you know those powers you have are meant to be used, right?" or similarly negative/"you're doing it wrong" framework.