I'm a proponent for quality and perfectly functioning rifles, which don't have to be custom.
I've been shooting and hunting with muzzleloaders since 1973 and I've seen the good, the bad and the ugly.
There's so much information available to the manufacturers, why do they continue to use and/or design inferior systems?
The Veriflame ignition is not new just to the Paramount. Searching on most muzzleloader sites will shed light on its past performance and leaking adaptors.
There isn't a modern inline muzzleloader manufactured today that shouldn't have or doesn't need modifications made because of lacking engineering design. What amazes me most, is the manufacturers know how to fix these issues, yet do absolutely nothing, then complain because someone calls their baby ugly. You mentioned Knight, which is another example of not fixing a long term and existing problem.
Frankly, there isn't a modern inline rife made today that isn't capable of 300yds. Make a trip to the NMLRA grounds in Friendship, IN and watch what a production rifle can do at 500yds. Knight holds many records at the NMLRA, including at least 3 if not 4 National Championships.
Knight, TC, CVA, Remington and Ultimate Firearms Inc. all produce less than 300yd moa rifles.
For myself and wanting a rifle that I don't have to constantly work on, fix, or complain about, I'll go with the modifications I know up front will forever stop issues, vs hoping I can get by.