The 6D cell magnum star xenon lamp is a much better choice than the 5 cell krypton lamp for the following reasons
1. The 5 cell krypton lamp will be overdriven very hard with 3 CR123's, maybe even instaflash. 6 D cell alkalines overdrive the 5 cell lamp, but alkalines sag under load, so 3 CR123's are going to overdrive it even harder for longer, therefore the lamps lifespan is going to be compromised, which will dramatically affect reliability overall, you'll likey end up buring the lamp up at a bad time.
2. The magnum star xenon lamps's construction is of much higher quality than the standard krypton lamps, the filaments appear much stronger and heavy duty than the flimsy looking ones on the krypton lamp. The overall build is much better, globe and base of the lamp is of higher quality.
I suspect there may be an issue with your xenon lamp, after a lamp takes a hard fall or drop the beam can be affected negatively, I suggest getting a new xenon lamp and giving it a try, if you aren't satisfied then go with a 5 cell krypton. The 6 cell xenon should not have a hole in the center, I have owned many of these lamps over the years and none exhibit the hole in the center when tightly focused, and I would be very surprised if you bought another lamp and it exhibited the same issues you're having.