there is absolutely NO way they can implement this change in 1 year without skipping a draft year, it just can't happen.
you have 2 choices, you cancel this years draft and push everyone back to 2006 or phase in the change gradually.
you can't have the 2005 cutoff by 9/15/87 and then make the eligibility for 2006 players born between 9/16/87 and 12/31/87 and have a draft with 3 months worth of players instead of 12 months.
what are you going to do hold a 3 round draft for kessel and anyone else born in those 3 months??
imo they will phase it in by changing the cutoff by 3 months each year...so 9/15/87 for 2005, 6/15/88 for 2006, 3/15/89 for 2007 and 12/31/89 for 2008
so by doing it that way you have 9 months worth of players for the next 3 years (which is an acceptable draft class size, 3 months is not) and by then by 2008 the new age is in effect.
this would also be the same thing they are doing for UFAs. ufa age will drop from 31 to 27 but it isn't dropping 4 years in 1 season it will gradually be lower...and you might notice that using my scenario the 27 year old ufa rule and the new draft age would go into effect at the same time.