In terms of sacredness I will say EA should respect the core gameplay of classic C&C (C&C95, RA1, TS and their respective expansions), to further expand upon this I make a description of the three main elements inherent to this core:
A tech-tree reliant upon different static production and tech structures build through a construction yard (A few of them may be capable to redeploy or have no need of power plants)
Collector-refinery based economy reliant in tiberium or ore fields (although tiberium spikes, oil derricks and other secondary forms of economy are welcome)
Infantry, vehicles and aircraft divided in tiers capable to work in synergy to create a functional fighting machine (at least a non-tournament gaming level)
I believe as long as you respect these three elements things will be good.