I will start by saying that level scaling was something unhealthy for the game but there are some issues by not giving xp to players who do raids, the main one is the lack of xp contributions that will come from Endgame level raids (TCC/TNA), a lot of players don't do much stuff or doesn't engage too much with combat activities (In my case, i do mostly guild housing time and prof for example), i only engage with teamwide content such as World Events/Graids and most of the time i contribute with xp to the guild, i believe that a lot of players are in a similar situation, where they don't give much xp to the guild and most of them comes from dungeons/raids/world events rather than grinding, so i have 2 suggestions:
-Make Raid Xp contribute at Guild xp after level 100
All raid scaling builds are for level 60-80, players at level 100 wouldn't benefit at all from this changes, so at least they should be able to contribute.
-Make Raids Xp scale
Raids enemies/bosses hp increase with level, why xp doesn't scale too?
-Make Gambits contribute to Guild exp in raw values
Since a lot of ppl do raids as their only way to get exp, this would aleviate the issue of ppl not contributing enought for their guilds xp.