It's one thing to have a LAV pop out of the sky in 15 seconds but it's a bit much for dropships and tanks.

Being able to quickly deploy these vehicles is a bit overpowering given the vast advantages they can give especially at the start of a game.

Using a dropship to deploy a squad in the ultimate vantage point should run the risk of that dropship getting blown to pieces, but when you're 15 seconds into a game how often is someone in a position to notice a dropship is even in the air let alone shoot it down?

When you're dealing with vehicles that can be game changers there needs to be a larger delay. Not only to prevent situations like above but also to avoid recall abuse. If someone jumps out of their tank to recall and immediately deploy their mildly damaged tank they should have to vulnerable out in the open more than 10-15 seconds before hopping back into their freshly undamaged killing machine.