I want to put a little thoughts here, (about Adrian's exit from the band)...
He wasn't happy with the decision to leave out the synths and the keyboards (for the next album) and return to the style of the early albums (like Killers). The idea was, after SSOASS album, they will have 3 months time to write songs for the next album and Adrian was happy with that decision, but when Bruce and Steve sat down to work they wrote ''Tailgunner'', ''Run Silent Run Deep'', and ''Holy Smoke'' for one day, thus the first plan was scrapped and the recording started pretty soon in a barn, with which Adrian again wasn't happy (and I think nowadays Bruce and Steve admit that they should have used a proper recording studio for the NPFTD album). And he wasn't happy with the songs being played live too fast back in 1988.
How can you leave a band like Iron Maiden when they were on the top, because I think SSOASS album was the peak of their creative powers. He maybe should have tried with NPFTD. I really wanted to see a Maiden album with Adrian in the 90's. The album could have been different with 3-4 songs co-written by him (not in the style of Hooks In You though).
If I'm not mistaken, when he played with the band on ''Running Free'' in Donington '92 he said that he shouldn't have left (he probably realized that he gave up from the best band in the world so easily and that was a mistake).
From the picture that I've posted of the interview with Adrian back in 1992, he said that he missing playing live, touring and writing and recording songs/albums, so two years after he was out of Maiden he was already hungry again for what he does best - creating and playing music.
But why Steve (and maybe Bruce too) wanted to ''return to the roots'' for the first Maiden album in the 90's..../ SIT and SSOASS albums were and still are one of the best albums of the band. Sure there were some fans that probably were not happy with the experiments on these two albums at that time and If I'm not mistaken, the sales of the SSOASS album in the US were not that good (SIT sales also, but better than SSOASS) and Maiden already played in a smaller venues during Seventh Son tour in the US (and during the SIT tour too). Maybe this was one of the reasons why Steve wanted to return to the style of the early albums (who knows), because otherwise, it does not make sense. SSOASS was a huge album and it's logic to continue in that way.../But the sales in the US of the NPFTD album were even worse than the ones for SSOASS, so not a good move. They even left out their legendary complicated stage designs from the 80's when the first tour of 90's started. And the style of the songs was more rock type, rather than heavy metal.