Nerfs? Not particularly necessary however just buffing people would really make the game stale out. Think of it this way, correct or improper as it may be: Buffing the lower tiers means that those people have access to the new content but will not instantly become viable. The top level, where people already are, will remain unchanged. Once the lower tiers finally do get up to the higher tiers, they will know exactly how to fight those top tiers because they've never changed, but it wouldn't be the same for the other side. This would make the lower tiers seem overbuffed in comparison to what was already the set level of the high tier.
Now lets look into the idea of nerfing and buffing. When you nerf the upper tiers, everything shifts a bit. Other high tiers have better MUs while the nerfed have to look into more options than what they had used before and may end out more effective because of it. Nerfing is the improper term, its more of a "less braindead" swap onto their kits. It forces them to use more of their character than what they already had. At the same time, buffing the low tiers brings them closer to the top where things are shifting and changing, and at any point one of them could very well become a contender. The game is being patched consistently, sure, but the changes as a whole are somewhat small and only affect one aspect of a character whom should have more than just that one option at their disposal.
The idea of only nerfing has its merit in everyone being on the same level as the lowest person, but never receives any real plus points with the communities because, lets be honest, no one likes to see their characters get nerfed.
That's just my view on it, but I feel like what they are doing judgement wise isn't as bad as everyone says. They are tweaking things that need to be fixed based on how the game is performing on a huge scale. Mind you, this scale is much much larger than what they had access to previously so its a given that many small changes would be needed. We cry now because of this and that, but the game is still young and there will be more patches later on. NRS has basically given their oath to adjust whatever they feel is necessary. Its not just the casual consumer base since, as its known, they brought no one but the top fighting game players in to mold the game. They are trying to find a nice middle ground where people can play the characters on both levels and it works both ways. Wait until they say "we are no longer patching" and THEN complain about what you see. Until then, everything is up in the air and they are trying to ease into the changes rather than simply mass-haul a batch of nerfs and buffs and then hope that it doesn't cause the engine to fail. You complain about -5 on low guns? Imagine, if you will, if instead of that one change they had loaded off a huge amount of changes all at once. The character would be completely different and everyone would complain "Oh he plays like this and that now, but I chose him because he played like whathaveyou.". They are being careful to bring everyone in line with everyone else eventually and make the game accessible at all levels for all players, but in different frames. I, for one, wish more people would do it like this. Maybe then Kano would still exist if they'd done it like this before.