In my opinion Oathmark is a way better rule set than Dragon Rampant. Dragon Rampant covers exactly the same size of battles as Oathmark, mass skirmish with a few hundred combatants. Dragon Rampant has a major split personality, at times it appears to want to be a skirmish game and at others a mass battle game where as Oathmark knows exactly what it wants to be and is written accordingly.
That’s funny because I think the same thing applies to Oathmark. It is described by the publisher as a mass battle game but the battle reports I’ve seen seem to be large skirmishes, there is figure removal and units seem to sometimes fight to the last man.
Yes, the advertising for Oathmark is “funny” describing it as a mass battle game, I can totally see how you would find it confusing if you have not played. I think it is described by the publishers as mass battle to distinguish it from the numerous skirmish games involving a handful of figures on the the market but yes you are right it covers mass skirmish or as you put it large skirmishes rather than mass battles. The difference between it and Dragon Rampant is that Oathmark knows what scale of battle it is covering and the rules are written with that in mind. You can easily avoid single figure removal by using markers or dice to show casualties. Fighting to the last man is possible but not probable except for units with very high stats and for those types of units would seem reasonable to me.