The reason that the Hollander is an issue, is that it is one of those few models that jumps up in tonnage from model to model (35 to 45 tons). Other mechs like the Marauder I vs II and Catapult I vs II do this as well, but plenty of the original versions have models to pick from and are already in the game in their original form.
The question would be, would you like (or be willing to see) the Hollander released as technically a Hollander II and the original loadouts (models BZK-3F and BZK-G1) be adapted in MWO for a II platform (such as the BZK-F5)?
The Hollander is specifically built around a Gauss Rifle in most iterations and anybody who has tried to shoehorn a gauss rifle in a 35 ton light (such as a Raven) knows this is rather obscenely slow for a light (probably like my much loved Cougar :/) or ammo limited. Combine this with a Gauss hand grenade in a side torso and the high alphas of the MWO game, and it could be pretty DOA unless mounting an Ultra 5 or A/C2 which kind of defeats the purpose of the chassis just to achieve a faster speed.
Other games like MechCommander realized this and that is why the 45 ton Hollander II was used (I thought I read it was possibly made for that game and adapted to lore, but can not find a source to confirm).
45 tons is far from ideal anyway with such a large weapon system, but at least it stands more of a chance.
So, would a Hollander II be an ok addition to MWO even if it had to convert the earlier chassis to 45 tons? Or maybe release the original regardless and make a fake variant to round out the 3 chassis under the Hollander I banner.
Or heck, just ignore it all together. it would be a shame for such a uniquely designed chassis...

What does everyone think?