I got no strong feeling for or against it; as such decisions are always made campaign specific.  Since it impacts everyone equally that's what's most important.  I will go ahead and detail some of my current thoughts on the matter however, as they have adapted.

You have mentioned before your dislike of disingenuous 1's.  And you're not wrong.  A 1 in either Guile or Know would be considered mentally disabled by modern standards.  Although in our tech heavy world, I wouldn't wonder if 1's in any of the physical attributes might have become alarmingly common.  Point being: Just not allowing a starting attribute of a 1 makes sense to me.  Or maybe by racial weakness only, if you still want minor flexibility.  A few of the DnD based games did something similar, where you still had build points to spend to go above average, but you started at average (not 0) as a building point.  The equivalent in this game of: you start at base 2 in all Attributes, and have 4 or 6 customization points to spend where you want.

20 build points is based on the average of a 1d4 rolling method.  A strictly average human would be 16 build points (all 2's).  22 build points is considerably above the average.  I would definitely consider reducing the rate of attribute bumps from leveling.  Regardless of whether you adjust the XP/session or not.

Which is a long way of saying a true human would look something like 16 build points at +1 every 50?/100?xp.  Amusingly, different RPGs differ a lot on how "normal" PCs should be.  Rifts always emphasized that even at level 1, your character is far above the norm, and has the abilities (or tech) to prove it.  Old DnD was the opposite, although newer versions have deviated far closer to (arguably even well past) the Rifts model.  

I do like increasing XP rates while reducing attribute rates, at one point with the goal of still keeping attribute ups on the 5-7 week mark.  Realistically skills should be more important than attributes for most tasks.  I know one DM was concerned from people throwing up too many new skills.  At this point however, at least in my brain, it does feel more like we have some established precedent on most things?  Still can be legit regardless; I don't know your opinion there.  If your larger concern is PC power levels, I will say this for the "over-powered PC" side of things.  Attributes are far more relevant than skills in bumping up the PC power scale.  I would rec toning down attribute up's regardless of other considerations, but especially if starting above average (20 or 22) and/or if increasing XP/session.