I actually liked him better in 2. In 4 they just made him a soulless edgelord
Raiden was handled poorly in part 2 AND 4.
MGS1 did an amazing job with Solid Snake.
The anticipation around MGS2 was incredible.
They teased us with the tanker mission in MGS 2 and then pulled the carpet out from under us. In place of this rugged, "man's man" type of solo super solider they gave us a baby faced skinny blonde haired kid (that if I remember correctly Snake even mistakes him for a woman the first time seeing him). The first time we even see Raiden they refer to him as Snake. Everything surrounding his introduction was poorly executed and left me constantly asking "so when are we going to go back to playing as Solid Snake?". Even the cartwheel mechanic in place of Snake's roll was cheesy. Throughout the story of MGS2 they mention this "Jack The Ripper" persona that we don't really get to see. Instead we get butt naked Raiden flipping around while Solid Snake is back to his iconic sneaking suit but we can't play as him. The narrative around Raiden throughout the whole game frames him as inexperienced and immature. His character was unlikable and a beta male especially when compared directly to Snake, and the enemies they were up agains.
MGS4 brings Raiden back to us in the most absurd overcorrection I've seen in any medium of entertainment.
Raiden goes from an almost pathetic loser aura to now breakdancing on the ground with a metal gear on each foot, slicing buildings in half, and has the strength of 7 supermans and 3 brock lesners. I'm not blind to what they were TRYING to do with Raiden overall, but it all was just terribly executed in my opinion and I've seen it be a common opinion online as well.
All of this actually sheds light on one of my main gripes with the series.
A huge part of what made Metal Gear Solid incredibly special to me was Solid Snake.
I always felt like the success of part 3 hurt Solid's opportunity to be back at center stage.
When I first played as Big Boss I was fine with it because "heck, he looks, acts, and moves, like Solid Snake".
But as the series progressed I feel like Solid never got the correct amount of time in the spot light and the series shifted heavily to "The tragic story of Big Boss".