Not really. You are forgetting that the main reason Surefire advocates not using rechargeables has nothing to do with the design of the 6P or it's intended use. It has everything to do with Surefire being a company based in America. If a customer gets hurt because they used a rechargeable in a Surefire light, Surefire then is facing a huge lawsuit. But if their lawyers can show that Surefire has an official policy of telling customers not to use rechargeables, then Surefire is less likely to lose.
The customer used a rechargeable at his own risk. Surefire specifically said not to. Surefire even narrowed the space inside some of their lights to make it difficult for customers to injure themselves by using rechargeables. (Those are all points that an attorney for Surefire will bring up in the event of a lawsuit.
I think we agree here (probably just the hypothetical attorney and myself): rechargeables are dangerous and Surefire does not want or intend for them to be used in their lights, well put.
I do not believe that your reason was the driving reason. Although it must have entered into consideration when the lights were slated to be upgraded to accept rechargeables. Personally, I think that Surefire thought that rechargeables are not dependable enough for military/gov't customers and require too much care and maintainable to have any net benefits. The gov't apparently agrees.
I will not address the reasoning behind that decision any further as I have no knowledge of it and it will lead the argument into unfounded speculation and unprovable opinions.
Solarforce on the other hand is based in China. Good luck suing any company in China if you get injured while using their product. Not picking on Solarforce specifically. However, the engineers at both Surefire and Solarforce know that the average customer is not likely to get injured while using rechargeable cells. Especially in a light designed to use just one of them. But in the rare event something happens, Solarforce doesn't have to fear a lawsuit from a customer in America. Surefire on the other hand, does. So once again, they are not functionally different. The first U2 models were indeed 18650 compatible.
I have two working eyes.
I'm sorry, but you can't say with a straight face that the light isn't a clone. I'll give you the variation aspect of certain Solarforce models. Especially the 2AA version. But where are the improvements over the 6P? Both the 6P and L2 can use the same aftermarket drop-ins. Sometimes it's easy to forget that the L2 is mainly sold as a host. No batteries, no emitter, no reflector. Doesn't sound like an improvement over a stock 6P.
I agree, international lawsuits against china usually don't amount to much, however I do not believe this is at issue. Solarforce, or anyone else, must promote their product and its dependability, and they must balance that against the customer demand for bleeding edge emitters and battery types. If I have learned anything on cpf, is that word of mouth advertising works. If your customers are unhappy with your product, the company is doomed. As little fear Solarforce has from American/EU lawsuits, they still have a controlling interest in spreading good reviews about their product and the only way to do that is with quality products.
The type of battery used determines what emitter and driver do, there is no way around that, if its an AA, cr123, 17670 or 18650. Therefore the type of battery used changes the operational aspects of light. The brightness, how much heat sinking it needs, etc. Surefire maximized the emitter for primaries for the previously stated reasons and for their primary customers who is the gov't who cannot depend on rechargeables. Solarforce does not have this restriction and work to meet the demands of the civilian market.
If anything the L2 can accept a wider array of dropins than the 6P because of this.
Also, Solarforce's variations of the 6P use a reverse-clickie. That sounds like a step backwards rather than an improvement over the 6P.
Variation to one person is an improvement to another, it depends on who's making the argument. I prefer reverse clicky switches. I have no need for a "tactical" momentary switch and am much happier with more levels. This marks another difference between the L2 and 6P.
Most lay people who buy flashlights are not the kind to spend 100+ on a single light, and when they buy they will prefer more modes instead of simplicity and rugged dependability. These are the same people that companies without defense contracts try to target. There are exceptions to this as collectors will buy what they like and become fans.
This goes to the core of who the lights were intended for in the first place. Surefire is a defense contractor first, and if they can make a quick buck off everyday consumers, fine. Solarforce is playing a different game. As I may have mentioned before there is probably a sizeable chunk of a multi-billion dollar appropriations bill that goes to surefire in exchange for their fine service.
This also explains why surefire does not "play the max lumen game".