Trooper Maximus:
Yeah, it is interesting the differences in how parties play, isn't it?
And feel free to use him - good luck in collecting players!
Mesh Hong:
I do realise that by the DMG, a monster is simply a collection of stats put together - so the damage expression and to hit need have no actual connection with the weapon the monster is being described as having.
That said, in the MM at the lower heroic teir, if the monster is described as having a weapon, it will usually deal damage appropriate to that weapon (well, except for minions, with their fixed damage). At this point in my campaign, I feel that is appropriate. Come paragon, I expect I will have dumped any such mentallity, but for now it fits both the "feel" of 3rd level and of my campaign.
For the weapon proficiency bonus, I don't care so much about that - though I do have a certain satisfaction when the results synergise so as to produce something that makes sense within the broader rules (as I was talking about before with being glad the sword and whip had the same proficiency bonus). That said, if I wanted to give a monster from the MM a specific weapon, I WOULD alter his to hit if his profile reflects using a certain weapon and the new one has a different proficiency than the first.
Both:
As for a longsword lacking flavour, I simply see it as a "generic medium sized fantasy sword". In this case, it would likely be described as one of those jagged sword blades like dragonborn tend to have in WoC's art. On the other hand, I view a battle axe as simply a generic large one handed axe, again to be described as needed. So, at least for me, a longsword is no more vanilla than the axe.
That said, I think part of our differences in preferring a sword over an axe or vice versa have to do with differences in what "plot role" he fills. I'm thinking that perhaps you see him as kind of a unique warboss, tyranizing other hobgoblins and only in power through the power of fear.
In my campaign, however, he's an actual slavemaster in that he is the one that bosses around the goblin's slaves - except for the other slave minders, he doesn't boss around other goblinoids at all. In such a case, I was thinking a battle axe is actually less intimidating than a sword. One one has nothing to loose (as does a slave), threatening their life isn't the most productive form of intimidation, yet is about all you can do with a battle axe. With a sword, on the other hand, you can show the slave that they do have something to loose - threaten to blind one eye, cut their face, heated to burn them with, humiliate them by cutting their hair... lots more possibilities. Additionally, I see it working better with the whip - when he hauls his victim towards him, he gets the extra attack because he pulls them onto his sword.
So, if I were playin the former, I think the axe would be perfect. - the latter, I think the sword works better. That said, if I were to use him in the former way, I would likely bump him to level 4 so that he is higher level (as well as being elite) than the rest of his followers.