Let's get this cleared up once and for all.
RAW -
If a power weapon has its own unique close combat rules, treat it as an AP 3 Melee weapon with the additional rules and characteristics presented in its entry.
Let's not distort the actual definition. Accept it for what it is.
When reading unusual power weapons it is clearly defined to ONLY apply to weapons that have special rules for close combat if it does NOT have any special rules affecting close combat then it does NOT count as 'unusual' and follows the standard rules for power/force weapons. There are many examples of weapons that have extra benefits in close combat that follow this rule.
So this brings me to my next subject.
The Ork Burna is a FLAMER first and foremost with a special rule allowing it to be used as a power weapon. There is no special rules for close combat, there are no additional rules to the power weapon or characteristics as such it is a normal power weapon by RAW.
The debate would reside in 'what type of power weapon does it count as' being that it IS a flamer is what makes it unusual but this again has no bearing on the "Unusual Power Weapons" rule because it clearly states it only affects those with special rules for close combat.
So again what does the Burna count as?
Do we all agree that the RAW definition of unusual power weapons ONLY affects weapons with special close combat rules and not just any weapon that has a special rule as it seems a lot of people seem to be interpreting it.
Given the way the Burna is built I am inclined to call it a Lance type power weapon. Though I can potentially see it being swung around like an axe or sword as well (kind of like a light saber made from an extended beam of hot fire) but it mostly screams lance to me if we assume that it has a pointy fire thing at the tip and it's used to pierce rather than to slash which makes a lot of sense to me.
This would indicate that a unit of Burna Boyz initiating an assault have S5 AP3 weapons on the charge. What do the rest of you think? And again let's stick to the RAW definition enough with the assumptions and misinterpretations, address the rule as written.