>>271698201st- Gen IV was made 10 years ago, considering I played it when I was 10 almost as it came out in 2007, you can figure it out.
2nd- Gen IV might not be the holy grail some sinnohfetuses make it out to be (honestly D/P is quite bad if you put it in perspective) but the content and long lasting changes brought with Gen IV are a quintisential part of pokemon, and without it the newer games would be far inferior and many more complaints would've come from missing features (the physical/special split, power balancing with new abilities and new evos, new items to create diversity in combat preparation).
3rd- Gen V is a mixed bag, B/W were mediocre as hell and very hit or miss, but B2/W2 are amongst the best in the series in a general concensus
4th-Gen IV sucks ass, I'll give you that
I'm done, I hope you're satisfied