is it worth improving crossover?

Take a look at the parts in your crossover, if they are of high quality, I would leave it alone. The fine tuning of a crossover is the result of time and effort by speaker designers, and most of the time if you are not sure, you will probably not improve on their efforts. But, I was advised to replace the non-polarized electrolitic caps (not really optimum for a speaker crossover) with solen polypropylene caps in my Infinity Beta planars and it made a great improvement.

You may try that, and get varied results. Although it may improve the liquidity in the treble, I will assume that being an already very capable product, the improvement may be neglible. If you can afford it polyproplene caps of the highest quality and large guage inductors can also improve the sound to a more transparent soundstage. By changing parts in an already optimized crossover can produce marked changes in the response, and the soundstage of your system. Case in point... do modifications at your own risk. For what it is worth, try listening to an already modified set, if you are lucky enough to know a dealer or a friend with a pair. Good luck.