Sadly, they did not play ATG in any of the shows in Yugoslavia, and they only played TLOTLDR in Belgade. It seems like even then they were not satisfied how songs from that album sound live.
I have, and have listened, to every SiT bootleg rated as 8+/A sound by taper, where score is reviewed and potentially corrected by trader himself. My personal opinion with problems in SiT live recreation, vs a hypothetical today's performance;
- Sonor tin can sound in the 1980s live. Vs. very roomy, highly reverberated and deep sound of studio drums. This is not true for last 20 years, especially when Shirley came in. It would be possible to recreate studio SiT drum sound today in concert.
- Lead guitar sound was ok then compared to the record and today it would be better. Maiden have enough staff to put the sound workload on them. When someone on stage flicks a pedal switch he don't necessarily care how many rack amps and effects were mangled in the backstage and how his audio signal changed routing.
- Rhythm guitar wasn't ok back then since it was completely chorus drowned and lacks the grit and distortion. On record the rhythm guitars were immense due to excellent balancing of acoustics and electronic effects, e.g. natural amp/room reverb gave it volume and widening while compressor gave it attack and spikes. If they did it today, they have three guitars on disposal where the bulk of rhythm sound can be through the usual Marshall stack, just not fully dry sound from all 3 at once to give it a spacey feel. When Smith plays Wickerman, there's a riff acting as intro and outro for the solo, on outro run he nowadays turns on something like flanger or phaser or chorus that makes it wet. Something like this.
- Bass, the usual business back then and now.
- Synths, offloaded to Keeney
- Vocals, Dickinson far better today than he ever was in the complete 1980s
So what's left? Stamina to perform the songs, and the willingness to put out 100% into them live from all band members. The problem is somewhere between those, where they might muster the stamina and recreate the energy live by putting 100% in the performance, which they won't do because obviously they don't rate SiT 100% collectively as a band.
Dickinson/Smith vs Harris argument over FOI tempo wasn't a political issue. Seems to me that Harris didn't feel the song at original tempo and had greater problems adapting to it than those two on the sped up version. The confirmation of this is today's performances where Nicko lays down an even more tight groove at the original tempo and Harris is extremely tight and into it, apart from the bass fills where he's still a bit too fast. Again this displays their reluctance of playing anything the whole band doesn't breathe with.
Simply put, no Alexander the Great because Harris and Dickinson don't like it, no some other SiT stuff because someone else in the band might think its meh.