In DS9 fleet battles, ships either also had "skinteight" shields - or no shields at all.
Again, a question of budget. It should be noted that the Galaxy class did have shield bubbles in the first TNG movie Generations, and the Sovereign seems to have that as well in First Contact. But in Nemesis, they moved back to "skin-tight".
Should we see this as a sign that shield tech is constantly evolving and changin back & forth, or just that it determines on the SFX team mood and abiltiies what they can implement?
In DS9 fleet battles there were no shields in effect at all.
It all seemed to be down to the SIF to hold the ships together as many ships were lit up in hull breaches from the first few shots, which seems to indicate total absence of shields.
In large scale battles its better to have contour (skin tight) shields. You don't absorb enemy fire that barely missed you. Its a logical concept, and after the dominion war shields should pretty much be of this type.
It's worth noting that, as previously stated, shields have generally been characterized by bubbles around the ship. It's only in big-production movies (and a couple episodic examples where the CGI was better quality than usual) that the shields actually conformed to the ships.
I would infer, then, that the shields are MEANT to conform, but no one ever had the time and/or budget to do so on a regular basis. An extruded bubble (ovoid sphere) is much faster and easier to render/animate than an extruded contour.
With that out of the way, I'd say that the majority of Star Trek fans would prefer the bubble, since it dominates on-screen appearances. It's familiar, which makes it comfortable.