Bearing in mind the Onieros is only slow when plated, perhaps a speed buff should be in relation to that, so a reduction on the effects rigs and plates have rather than an overall speed buff?
Enough to get it nearer 2k m/s which is a similar speed to most scimitar fits but with a better tank (think 40k ehp is usual for scimitars?)
I mean currently Onieros is ok, it fills a very niche role but yes, there is nothing to really seperate it from other logistics to make it an actual viable choice in a varied amount of fleets.