Vaenyr
Ancient Mariner
They don't have to be someone's favorite to be popular. All of those I mentioned are popular with the fandom. Total Eclipse is regularly talked about, especially in comparison to Gangland and how the former should've been on the album rather than the latter.Are they? Never heard anyone mentioning these songs among their favourite.
Thread is not about Maiden songs we dislike in general, but popular fan faves we dislike. The Parchment, Isle of Avalon and the mentioned ones don't really fall into that category I think.
Sun & Steel is on one of the "golden age" albums, so it automatically gets a boost and unlike Quest For Fire which gets memed and clowned on because of the lyrics, it doesn't have any obvious shortcomings; so yeah, it is rather popular overall.
Speed Of Light is pretty popular as well. Isle Of Avalon is consistently seen as one of the best songs on TFF. The Parchment gets a ton of love as well, at least here on the board and on the subreddit.
I specifically chose to mention those songs because they fit with the criteria of the thread. If it were just about songs I dislike, regardless of popularity I would've chosen different ones. You can go through the song rankings subforum and see how the various songs fare, if you're curious. Obviously very anecdotal and not a big sample, but still quite interesting.