(Hena @ Jun. 01 2008,17:19)
QUOTE
Against MW heavy army the marines should go with their heaviest units. Terminators and Land Raiders. This set makes it easier to wield Land Raiders (while Terminators are very much used and gain a point increase to balance them especially after the new MW assault rules).
The point here is that in tournaments you enter the competition blind, and so need to provide a list that will work against any anticipated opponent. IMNSHO, it is this concept of "balance" more than any others that is critical in list design, and is at the heart of many problems. Sure it is quite possible to design an army from virtually any race that is capable of defeating a particular "bogie" army like TRC Siege list or the Tau army of Doom (whatever that is 
), but in doing so the army usually becomes extremely unbalanced in other respects - (Tiny-Tim admitted as much when he did so )
The issue here for the Dreadnoughts is that adopting "non-MW" armour relies on the MW effectiveness in the other armies being reduced in sympathy (through range reduction, points increases, reduced shots etc). If this seems unlikely in the short term, then perhaps 5+RA is warranted.
(Indeed, given the other fluff etc and the fact that when added to formations, Dreadnoughts tend to be the only AV unit in the marines formations, even 4+RA is possibly arguable - though I am sure that most would reject this as several steps too far 
)
