The fact that server mods almost always need client components (blocks, GUIs, sprites) makes Minecraft low quality. See Blockland.
Au contraire, I feel that it makes the quality of the gameplay experience better.
The fact that a client component is necessary for items and other basic functionality prevents people from perceiving a client component as detrimental. As a result, we don't have so many mods that are based entirely around using commands to achieve things. Bukkit of course encourages this mindset of "vanilla compatible", resulting in a lot of hacky, non-user-friendly mods - re: 90% of Blockland mods that
aren't just weapons.
Just imagine if TFC were implemented in Blockland without a client component. It'd still be loving horrible.
