I’m a fan of the battle grid, if for nothing else than as a visual aid. I suck at describing location and positioning, and my brain mangles similar information that I get from others. If you describe to me an onyx statue standing in the northwest corner of a hall, I’ll be imagining an ivory figurine magically floating on the southeast edge of a dais. That said, WotC D&D does create certain battle grid oddities.
Flanking is a Couple’s Sport
Triple teaming your enemy is better than double teaming him, right? And yet by the rules triple teaming, or quintuple teaming [and so on], grants no advantage to the third [or fifth, etc.] wheel. Because, against normal-sized enemies at least, you have to be exactly opposite of your ally to officially ‘flank,’ flanking is a couple’s game.
Mind the Cardinal Points, Ye Flankers
…Because it’s easy to escape flankers who fight from combo-compass points (NE/SE/NW/SW). Your victim need only shift (aka 5-foot step) toward one of the combo-compass points, and then he’s free to blast you or flee! But if you trap him from the basic compass points (N/E/S/W), he’s in trouble. Because no matter which way he shifts, he’ll still be adjacent to at least one flanker.
The Ten Foot No-Charge Zone
This oddity is unique to 4e. Because creatures can’t charge just one square, smart players and DMs can exploit certain conditions and forced movement to put enemies in the ‘no-charge zone.’ There’s even a CharOp build that specializes in creating this effect; it’s called the polearm momentum fighter. This is how it works: knock your target prone from two squares away with your polearm. When your target’s turn comes up, he can use his move action to stand up. But he can’t attack you; because even though you’re only two squares away, he can’t officially ‘charge’ because you’re too close. (Dazing your opponent, and using forced movement also works, but it’s not as easy.)
This creates a weird tactic where the fighter says “Okay guys, I’m tripping this guy, so stand exactly ten feet away so he can’t attack you!”
As much as 4e fans explain it as abstraction for the sake of simplicity, square fireballs still look silly. Of course, nothing’s perfect; counting squares by 5-15-20 feet gets annoying quick, and hex grids are sacriligious in D&D.
Hex Cone Sectors
Despite being sacriligious, hexes do iron out some of D&D’s grid oddities, but they have one of their own. Cones look really good on hex grids, because hexes naturally create triangles. But a character wanting to cast cone of cold for example, will find that a neat triangle template will only fit into one of six distinct ‘sectors.’ This can create weird situations where a caster can’t hit two targets because they’re in different ‘sectors,’ even though they’re right next to each other.
The sector oddity can be helped by using two different cone templates, one neat and one bumpy, but at the end of the day it’s a matter of picking your poison. Do you want the battle grid and its oddities, or the vaguery of pure description?