Have to agree with Dobbsy here, to some extent. In a way this actually revolves around the 'vanilla' codex Marines list and contents as much as the various flavours of other lists. As far as I am concerned a new (Marine) list is appropriate where there is a reasonably significant change to the units and/or formations available in that particular army variant or campaign.
Here the IF are presented as the Marine "SWAT" team, a force that specialises in sieges, assaults in space etc. The key here is that they have access to specialist Weapons - that are presumably not available to other Codex.
As with the BA, perhaps we could tailor the list to some extent to force the choices being made. In this case, perhaps between long-range artillery and ground attack fighters (or something along similar lines).
However, the list is already treading a very fine line between the need for particular weapons and tactics to match a particular situation, and a general list of kit to match all situations - that rapidly expands to become the standard Marine codex (which after all is intended to be capable of a very flexible response to *any* situation)
As for new units etc, please comment on
this thread, where I am proposing an approach to allow us to test and potentially include new GW units in a more controlled manner.
