The Gunner Corrupt Rescuer is a common discussion point, like any other highly-used, very effective unit. However, she's also a character with an atypically large amount of hard counters. She's commonly discussed, so a search through the forums should find many threads and discussions on the matter. While some of her hardest counters are scheduled to get nerfs with this tuning update, they'll still be very effective against her... and we'd much rather add/improve other units to be as good as her on defense (or be interesting alternatives) than try to bring her down a notch.
As for the Sentinel Soulless Demon, that character has already been discussed
to some length, and while most of the discussion happened around the time where Taunt was much more problematic with Mummy Eddie, the overall sentiment is he's really not that big of a deal, which is why he's stayed unchanged. One of the most common complaints was him Taunting more than he should be (which he's not), and with even more removal/steal beneficial effect options, and more viability/availability of Cleanse buffs (current combat hang bug notwithstanding), he's decided solid, but not overpowered. Angel of Fear continuing to be popular and the rise of strong Warriors like Warrior Newborn of Light and Nomad continue to be a thorn in the Sentinel Soulless Demon's side.