If looking at the content differences between 92.03 and 100.02, these are the Gameforge patch notes following 92.03 with some of the main highlights:
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(skill rework plus some QoL adjustments)
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(new Draakon Arena dungeon, new training ground system, new jewelry [which a lot of folks hated due to additional RNG rolls], new PvP zone (Exodor Core), Partner adventure system, gathering system revamp)
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(64-bit client, Unreal Engine 3 updated to one of the final licensable builds; basically the same 5-digit build that Elyon uses compared to the 4-digit one it has been using for years); asynchronous loading is one of the biggest improvements along with less restrictive level of detail (which is why the graphics fidelity is actually higher with the same assets so long as your system can handle it), Commanders Residence raid, additional training dungeons, UI improvements, some class balancing)
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(new Forbidden Arena dungeon, new training dungeon, additional new jewelry that weren't released in patch 97, some class balancing)
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(TERA Battle Arena game mode, dungeon cost changes, enchanting cost changes, new etchings + new etching crafting system)
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(new character selection screen, 20-player Harrowhold raid [previously was 30], TERA Battle Arena enhancements)
So cumulative wise since 92.03, there's a lot of additional content along with changes to in-game systems, QoL improvements, etc. Yes, no 32-bit client as of v97. UE3 build upgrade was because at the time, there were longer term plans to work on enhancing the graphics (they utilized the build used for Elyon since Bluehole wrote custom extensions for it to get additional performance out of it; you can see this in Elyon with the seamless transition from open world to a single player story instance where it is stutterless). All prior unlocked dungeons can also be re-enabled (though reworked dungeons that were cycled back in over these patches, will likely supercede the dungeon that was available before; so possible changes to bosses and mechanics in addition to hit point/damage changes).
Basically, worthwhile to move forward.