Am I totally out of line to think that this change is a DESIGN change that will affect balance? A Design change that will not improve the game objectively. the most convincing argument is 'it will speed up the early game'. does early game need speeding up? i don't think so.
This is a SUBJECTIVE DESIGN change that WILL affect BALANCE. Maybe it will somehow fix all the problems. Probably not since you know... logic. Yes, I should not have quoted thunderhun's quote fully, i only agree with partially so my position might not be as clear but all I am saying is that:
This is a SUBJECTIVE DESIGN change that WILL affect BALANCE most likely negatively.
You can't make any meaningful change to any competitive game without there being some sort of impact on balance. Balking at design changes because you don't know how they will affect balance is a great way to dismiss all but the most miniscule of incremental changes. Your concerns, like those of others in this thread, stem from a fear of bad balance that is irrational and near-sighted. You're taking a one-month view of a change when you need to be looking a year out. Can you give me a reason this change doesn't work that isn't "it might affect balance in some way for a few months"?
From my perspective, I see a lot of objective unit control improvements that this change brings. You'll be able to double-tap a building hotkey and center your camera on the exact location where your units will spawn. You won't have to worry about southern and eastern spawning positions forcing you to wait seconds before units walk into your camera view so you can select them, while your opponent in the north or west has no such delay. You won't have to worry about certain unit abilities arbitrarily being unusable until units cross a magic line, before which they are on the map but not "on the map". You won't have to wait a completely random amount of time between when a unit finishes construction and when that same unit is fully usable, an amount of time that is different for every starting position on every map. And you won't have ridiculous antipatterns, like juggling rally points to choose spawn locations and retreating the moment units enter the map proper in order to save a few seconds, that add artifical complexity that is neither fun for players nor entertaining for spectators.
All of that means quicker, more consistent access to your infantry units and their abilities; it's hard to see how that can be construed as being bad for the game. But when you're obsessed with seeing balance impact in every little thing, you lose sight of how changes can affect, and improve, the game on a more fundamental level. Balance will go up and down whether this change is made or not. This is an opportunity to strengthen the game's foundation by removing some frustrating control mechanics. The long-term impact is far more important than the short.