1. Weapon timers. Currently, the delay before swinging your weapon is derived from the previous weapon you had equipped. This allows people to use a fast weapon like a katana, then switch to a halberd and only have to wait out a katana swing timer before the hally wack. This means it’s often a better idea to run in with your katana first, to get that “free katana swing”, before you switch to the fast hally wack. This is one of the first basic tactics you pick up when PvPing here.
This phenomenon was completely absent during T2A, because you had to wait out the slower weapon’s (halberd usually) swing timer regardless of the other weapons you had equipped before or after, making it pointless to switch to your katana after a hally swing (you might as well just get another hally swing in). Tank mages would exclusively rely on their halberd during combos. Katana play was usually relegated to low mana situations.
Honestly, if everything else remains constant, I would rather keep it how it is now, or reverse the phenomenon (hally then fast kat swing), because it’s more fun, and introduces more tactics. This also ties directly in with how double hits work here, which is also off. People did not use a faster weapon (katana) to initiate a double hit in T2A. The anecdotal evidence on the “Stamina Loss and Swing Timer” thread corroborates this claim. The mechanics of true double hitting are still pretty mysterious to me, and to be honest, I did not use double hits back in T2A.
2. Auto-unequipping when you target a spell. Currently, the game automatically unequips you (bypassing any normal object delay) when you target a spell, either through a macro (last target/target self/etc) or by manually clicking. Before the advent of third party programs and arming macros built into the client, people used to manually drag weapons to and from their paper dolls. I’m pretty damned sure you couldn’t just target something with your weapon equipped and it would magically fall into your backpack then release the spell.
3. Item usage with a target cursor. Currently, you can use items like potions and pouches with a target cursor up, and not lose the cursor.
4. Disrupts. Already beaten to death. Debuffs and harm were a consistent and reliable way of disrupting spells.
Evidence for debuff disrupts (it is a UO:R (Jul 2000) screenshot, but no patch notes on the changing of this functionality suggests it existed prior to UO:R):

Evidence for magic arrow/harm disrupts (taken in Jan 2000):

5. Horse stamina. Horses have a ridiculous amount of stamina, or the rate at which it is lost is way too slow. I have not been able to run my mount out of stamina during any normal game play situations (and I usually run around like a bat out of hell). In T2A, your horse would run out of stamina fairly quickly (I’d guesstimate maybe after about 30 seconds of solid galloping), and I bet many of us have keen memories of guildies lagging behind to feed their horse an apple.
6. Self disrupts. Currently, any type of equipping is blocked during the spell casting ritual. I believe in the era, you could equip anything while casting a spell and disrupt yourself.
Minor issues:
7. Gate dispelling. When using the Dispel Field spell on a gate, both sides of the gate are dispelled. Only the side which was targeted should be dispelled.
8. [frozen] indicator. This currently manifests itself in the form of a separate string above a person when you use the “all names” macro. This may seem very nitpicky, but the reason I’m bringing it up is because this confuses Razor, which will then think the person’s name is “[frozen]”. You can see this in the Razor hit % indicators (it will say “[frozen]’s stats: [82%]”) and if you are in a party with them, their name will appear as “[frozen]” in the Razor auto-map. The correct way to display the “frozen” status is with a suffix of “(frozen)” on the same line that displays the character’s name.
Evidence:

9. Failing meditation at GM. I don't remember this happening. Anyone else?
10. Murderers. Reds should have a "The Murderer..." title and cannot be in an Order or Chaos guild.