Giran Clan Halls are perfectly fine - you see, the shops don't start spawning unless you're close to them and/or are in your vision radius. The only time you're - ever so slightly - affected is when you're running straight from CH to GK, and even then (map):
a) Mithril Chamber completely unaffected
b) The Bronze Chamber an Silver Manor affected only marginally affected since they're running on the less used south/eastern part of the square.
And so the only one who are affected - and I'll get to this word later - are members of The Silver Chamber and The Golden Chamber. That's two clans compared to the rest of the server, which just doesn't put enough weight to the other half of the scale to really make it an argument to consider.
But now let me get the prime reason why this argument doesn't really hold up in practice - if you're free to do so, please teleport to the Giran Harbor as it is now and without any delay, run to the northern gate. Was it really such a bother? I bet it wasn't, because the reason why you, or really anyone consider Giran Harbor as such cancer to stay in is because we go there to shop, and thus we let the shops load. And so - if you're really just running through, you don't load enough shops to make it a relevant issue. Mind you - not sure if you've noticed, but the shops don't load even if you're not directly on the window, so logging with several characters isn't issue either.
Also - not sure if my mind is playing tricks, but weren't Giran Clan Halls always considered the most prestigious ones exactly because they were in the middle of the bussiness zone? And that's how it's always been ever since I started playing 10 or more years ago, at the time there were just as much or even more shops in Giran and people had generally much weaker PCs. Did anyone having a Giran Clan hall complain back then? They didn't. And you know why?
Because it has always been a part of the game. And this exactly is the prime reason why trading center needs to return back to Giran. Giran Harbor is a custom zone - yes, it's comfortable, but it DOES NOT BELONG to a classic Lineage.
But even though this reason itself is enough to move the trading zone back to Giran, there're much more of them - importantly it has infrastrucure of a trading center - every single NPC that you need for bussiness is in Giran Grocery for Soul Ores, Spirit Ores, Gemstones etc., weapon/armor shops when you want to crystalize something, the NPCs for talismans, NPC to give your weapon an SA etc. it's just all in there. But importantly the zone is not affected by fishers and their pets who are making the Giran Harbor hell to really go there - the fishing areas are smartly divided by several walls and are quite far from trading zone so they don't affect the loading at all - whew, it almost sounds like somebody wanted this town to be a bussiness center or something.
The trading zone needs to return to Giran as soon as possible; it's not just a question of nostalgia and the roots of Lineage II - Giran Town is simply superior trading center to Giran Harbor in pretty much every aspect.