And I have no problem with you painting Shepard as a bad leader. I believe it is subjective though based on your own experiences and knowledge of military life as it exists in our world. I believe you when you say that most soldiers fighting in a resistance would not look up to Shepard as some kind of ultimate hero because they know that the real heroes are those fighting the trenches day-in day-out with very little reprieve, facing all the same dangers without any of the comforts of a civilian designed warship. I think they would be wrong to discount him as a hero altogether though. He may not be any more heroic than your average soldier but he is still willing to give his life to protect the galaxy and ultimately does in 3 out of four endings. As for him being the leader of the fight against the Reapers, I don't necessarily see him this way and neither does Shepard himself (depending on how you play). He is ordered to the Mars archives and then when the plans for the crucible are discovered, he is ordered to build alliances and gather reinforcements and resources for the war. This is and has always been a role forced upon Shepard as a result of pure chance. He has always been the "everyman" soldier thrown into exceptional circumstances and forced to take an unorthodox approach to dealing with the whatever evil he was faced with. The fact that the rest of the galaxy needed to have one man they could point to as their saviour was none of Shepard s doing. It's basically PR and goodwill needed in a time of crisis. I'm glad the soldiers on Earth reacted positively to Shepard upon his return because while neither I nor Shepard saw him as being the paragon of the human race that everyone else wanted him to be, he still successfully carried out the most important mission in galactic history and saved trillions of lives. If said front-line men and women can't give someone respect and appreciation for that, then they deserve a sync-animation kill by a banshee.
And that's the sort of sentiment that makes for a horrible military narrative character for anyone familiar with the military.
Case in point: Shepard acting like the 'everyman' character isn't just wrong, but in reality it can actually be offensive and aggravating. When an elite soldier or officer acts like they are the baseline, it implicitly makes everyone less capable than them to be substandard. 'Not as amazing as me' becomes 'not meeting the standard.' This can be useful: an officer in particular should be a bar for their soldiers to reach and surpass. But it can also be misleading and harmful when the bar is set so unrealistically high that no one else will be able to reach it. Goals needs to be both realistic and achievable, and 'the best' isn't a good one. When Shepard, super-cyborg with top 1% ability and equipment and support says 'I'm just the same as you' as if you're at the same standard, and you know you aren't, he or she is really saying 'you're not good enough if you can't meet the standard.' Which they won't.
Soldiers dislike false modesty and association as much as anyone else. They don't like it when politicians try to equate themselves with the everyman, they don't like it when officers pretend they're just another Joe, and they don't like it when rear-stationed soldiers claim to be front line troops. And if you think that means they deserve to be murdered by the enemy they don't have a stealth ship to get away from... well, they probably wouldn't like that either.
Except they'd be dead. Because they aren't Shepard, and Shepard isn't an everyman on the front lines like them.
Which, to bring us back around to Dragon Age in a tangent, is why I hope no one falls for the Inquisitor's military amazingness or swoons over how they're just another soldier like the rest of the soldiers of the Inquisition.