According to the article in Dragon #307, the change in the hold spells was to illiminate the on/off aspect of the spell. The spells recieved alot of feedback as a killer spell, so WotC decided to look at it.
Quoted from Dragon Magazine #307, without permission
"This proved problematic on a variety of fronts...by rendering a character or monster out of a fight for a period of time...it seldom worked that way...paints a big fat target on the creature. PCs get themselves in position for a coup de grace as quickly as possible...and the DM might do that, too."
"...until the duration runs out, the held creature gets to make a saving throw every round..."
"This addresses all the problem areas of the spell fairly easily...it does encourage the foe to attack the target quickly, but a coup de grace is a full round action. A charcter has to get in position one round, then perform it the next. That should give the target...at least one probably two, and maybe more chances to break the effects..."
"...this also solves the 'I'll go for the bag of chips' problem. The player...stays at the table and every round, rolls a die. The hold spell still has the whole 'on/off' issue, but as generally lower-level spells, we have to live with that sometimes."
No mention of reducing/raising the spell level.
Myself, I would think Haste getting changed would be the bigger conversation piece.
Partial action - gone
+4 to AC - gone
replaced with:
increase movement by 30'
+1 to attack roll
+1 to dodge
+1 to Reflex save
They feel Haste as a third level spell was too powerful. Maybe. So they fixed it, to bring it to par with other third level spells.