You know... it might not seem so lately, but I am still a DT fan and they are one of my favourite bands... And I'm really crazy about narrative music in general, be it individual songs, opera, operetta, musical theatre or concept albums.
But although I still like TA and give it a listen from time to time, it's a fail in my book. Really, it has few of the stuff I like DT about and possibly even less of the stuff I search for in o/o/m. For one, the narrative itself is pretty shitty. I really appreciate the way music can supplement the poetry and the drama in development of the characters and moving the plot forward... but TA is seriously lacking in those regards. This is a concept album that's over 2 hours long, yet the basic story with all the character development could be told in an hour or so (let alone the fact it's so clichéd that Ratatouille feels like a subversive deconstruction of Parisian life in comparison).
That's not just a DT problem - in all honesty, Operation: Mindcrime might be a very cool, melodic and altogether great album, but the concept/plot is very meh. Like, what development is there to be talked about that couldn't be covered in about 20 minutes, seriously?
Mercy Falls by Seventh Wonder is like that too.
Honestly, even Scenes from a Memory, possibly - I mean, really, how many songs are really about the stagnation of the plot?
I'm saying this primarily comparing this stuff with both opera (where, indeed, you get people singing a whole song about how they feel, but also the play ends in a very different way from where it began and you get a lot of development throughout) and musicals (Les Misérables, to name just one, is nearly three hours long, yet it manages to capture the characters, the themes, the main storylines and the general atmosphere of a 1400-page-long novel. Sorry, but the Frenchies win here).
AMOLAD, thankfully, is a concept album but only in the thematic way. So no narrative is needed and the album feels mostly like a caleidoscope of ideas, wonderfully supplementing one another. Also, it's musically much tighter.
TLDR - Maiden and DT are both bands that are with me for almost as long as I remember and I usually set them apart when I name my favourite bands, because I honestly can't judge them on their own, because they've been in my life for such a long time... yet AMOLAD is the best Maiden album I ever knew and I'm probably not going to change this particular opinion anytime soon and TA is one of the worst DT albums overall (though still very cool and enjoyable).