Throughout the game, every army has its own uniquely-flavoured vehicles. Necron vehicles, for instance, have a very cohesive look (with the exception of the monolith), and the Living Metal rule ties them all together. The same can be said of Eldar vehicles with things like Spirit Stones and Star Engines being instantly recognisable as belonging solely to that race. Even other Imperial factions have a more distinctive flavour, even if it's just from their names; if you'd never heard of a Wyvern before, you'd still be able to guess which army it belongs to.
The exception is Space Marines. Years and years of vanity projects by Rules Writers and Miniature Designers have left the Space Marine vehicle range in a right mess. Names come from a dozen different sources, you get endless variations on the basic Rhino chassis which seem to share nothing as far as rules are concerned, and you frequently get several vehicles doing to same job but for different prices.
The solution? As far as I'm concerned the whole range needs trimming down and refining, and something needs to be done to make it more cohesive. This is also an excellent opportunity to finally answer the question of why Space Marine vehicles are so apparently inferior to Imperial Guard ones.
1. Shunt profiles together from Forge World. The models have been integrated into the core range and we have constant adverts for Forge World units in
GW's own publications already; there's no reason why the rules couldn't just be folded in to the core range. The Predator, for example, could easily have a clause added to its army list entry saying something like 'One Predator per army may replace its Autocannon with an Executioner Plasma Cannon at a cost of 30pts'. This should reduce the number of books you draw from when building your army, and allow issues of balance to be finally addressed.
2. State once-and-for-all the core profiles of the Rhino chassis. Rhinos and Razorbacks use the 11-11-10 'Transport' profile, Whirlwinds and Stalkers use a reformed 12-11-10 'Artillery' profile and Predators and Vidnicators get a 13-12-11 'Battle Tank' profile. Incidentally, you can probably stand to lose the Hunter altogether; we only need one
AA gun, and frankly that could be covered by a Whirlwind Hyperios upgrade.
3. Space Marine vehicles are supposed to be hyper-advanced. I understand the unwillingness to mess with their core profiles (although that's exactly what I've just done), so this could be done by rolling out the Power of the Machine Spirit rule, but changing it slightly. Here's my idea:
Power of the Machine Spirit: Space Marine vehicles incorporate highly advanced and ill-understood systems which can take partial control of the vehicle when required. These are not the savage war-spirits of the Titan Legions, but cold and aloof personalities which intervene judiciously in the way that the vehicle needs most at a given time. The legends of some such Spirits are millennia long, and they are considered as much a part of the Chapter as any Battle-Brother.
Once per turn, a vehicle's Machine Spirit may perform one of the following tasks:
Fire one of the vehicle's weapons at BS 4, regardless of any crew effects it may be subject to.
Move the vehicle at Combat Speed, regardless of any crew effects it may be subject to.
Attempt a repair of either a weapon which had previously been destroyed, or an immobilised result, or a single Hull Point of damage suffered earlier in the battle. The effect is repaired on a 5+.
Obviously points costs can be adjusted to account for the relative increases in power, but I'd like to know what Dakka thinks.
TL,DR: I wish Whirlwinds were still cool.