The Incredible Hulk in 2008.
Marvel went in an unexpected direction with the iconic character in Smart Hulk".
An obvious problem with this arrangement is that Bruce Banner is stuck at eight feet tall, and can no longer revert to his human form. One benefit from this, though, is that since he doesn't hulk out anymore, he doesn't destroy his clothes on a regular basis. Typically when this would happen in the MCU, Banner would wake up naked, forcing him borrow clothes from a different character. This happened during Harry Dean Stanton's cameo in Thor: Ragnarok, and Avengers: Infinity War , wearing clothes from the likes of Tony Stark and Doctor Strange (h/t anilsoi11 on Reddit)
However, it wasn't an issue at all in Avengers: Endgame, considering that Bruce doesn't "hulk out" anymore. Another way that this change was a positive one for Banner was that he was able to rely on the gamma radiation in his body to wield his Iron Man's Infinity Gauntlet. The Hulk by himself could have withstood the physical effects, but he wouldn't have had the intelligence to use it properly. Also, Banner presumably has access to Hulk's strength, but doesn't get to use it since he never fights Thanos or his army in Endgame.
All things considered, the merging had a good outcome for Bruce Banner, but unfortunately the same can't be said for the Hulk. Smart Hulk may have had Hulk's physical appearance, but his child-like personality is gone for good. Essentially, the Hulk was killed by Avengers: Endgame, and with his MCU arc now completed, it's hard to imagine him being restored to the status quo (despite the reports that Ruffalo will reprise his role in Disney+'s She-Hulk series). Being replaced by the "Smart Hulk" persona robbed him of his long-awaited (and desperately needed) rematch with Thanos and kept him from having any screen time.
