Some of it takes the form of a suggestion box entry. There is a call for clearer language in Rule 16(a)(1) where there appears to be an allowance on the part of the RNC for either proportional or winner-take-all allocation rules (regardless of timing). That is perhaps not completely consistent with the restrictions on winner-take-all allocation laid out later in Rule 16 and penalized in Rule 17.1
Other points -- like the one on the width of the proportionality window -- show some resistance, but not outright defiance. The impact of an all-proportional March versus a half-proportional March (March 15 cutoff) is indeterminate. It may or may not slow down or speed up the pace with which the ultimate nominee accrues delegates. Much of that depends on the dynamics of the race -- who is still in the race, what the terrain is (what the sequence of events is).
The fact the tone is this way on these proposed rules changes may be a function of either the scale of the change or the fact that the issues in the proposed changes have been discussed and find some consensus within the Rules Committee and/or the RNC.
The new wrinkle, and where the discussion in the Rules Committee gathering at the RNC winter meeting this week in DC is likely to be interesting,2 is the change proposed to Rule 20. Peter Hamby brought this up in his rundown of the proposed changes a few weeks back. This is the rule that accounts for the certification of the election/selection of delegates.
The reason that this is somewhat contentious is that this is the potential provision that would allow state Republican central committees to select delegates in states with late primaries that may conflict with the logistical requirement of having delegates in place 35 days before the convention. In other words, this is something that is necessary in order to lay the groundwork for a late June or early July convention. [FHQ has more on this here (in the discussion of providing incentive to late primary states to move up).]
Blackwell views this as an overreach of the RNC, infringing on a state's ability to select delegates to the convention as it sees fit. Whether this is eventually a contentious discussion at the meeting remains to be seen. Much will depend on the calculus of RNC members present and voting on the change. Will they see Blackwell's way or will they value the earlier convention that Chairman Priebus and others with the party want?
1 Mr. Blackwell also points out the inconsistency regarding automatic delegates in Rule 17 that FHQ described here.
2 FHQ does not necessarily mean heated or controversial here. Rather, it may take some time to unpack and explain everything on the proposed rules change in the context of the meeting.