The problem with magic is that we see it as just that - magic. People in Yliakum, however, see magic as an everyday part of life, almost. We, as players (and I suppose as Yliakumites, too) don't know the limits of magic - what you're "allowed" to do, and what you're not...where your boundaries are, how far you can go with it, what you can do with it. If there was a glyph to make someone explode from the inside, it would seem perfectly natural for the people of Yliakum, but for us, it isn't realistic in the least.
Where's the problem I mentioned earlier? The problem is, glyphs seem to have no real limit. They can do anything that they're designed for, but there's only a "line" that can't be crossed because there may or may not be a glyph for the desired person-exploding effect. Therefore, people create their own spells outside of the glyphs in order to get their desired effect. Is the effect realistic? To them, yes, to us, no. In order for magic to seem realistic, there needs to be more of an explanation, more of a design scheme, than just "it's a glyph, it's a tool, you use it, no more questions".
What I'm saying is, when people are limited to just glyphs, they feel like they should be able to do more, therefore...they do. They create their own rules to make up for the lack of rules ingame so far, and try to explain to people "my character can create a hole in the ground by using mana to..."...hope you get my point.
Edit: Now that I've read a few posts...

To implement magic, you need to quit looking at it as magic. To us, like I explained earlier, magic isn't realistic. To the people in the world where you're trying to implement this magic, it is. Therefore, instead of calling it magic, call it something else, and give it rules where "okay, you can create a fireball, but you can't make your eyes turn red", "okay, you can make the sky rain fire, but you can't condense someone into a tiny ball of flesh".
"Magic" needs rules and limits in order to work logically in a game, especially a roleplaying game. I really don't see many rules for Planeshift's magic; it seems to be able to do everything, but only if there's a glyph. Glyphs themselves don't have much explanation, since Talad suddenly creates all of these weird little objects that can make thorns stick out of your skin or water circulate your body...why? And something else I noticed with PS - when questions about magic are asked, they're answered with "it's magic!" (see Levrus); if that's the case, magic seems even more unrealistic to the people of Yliakum than it does to us, and if that's the case (with no real effort being made to understand it), then that's...well, fail.
And yes, I ramble on a lot. I type what comes to mind, so I hope it's legible.