Most of the Primaris units so far also cost nearly twice as many points as their older counterparts and have unit sizes no larger than a 5 10 model maximum (including the Serge). This strongly suggests they will be more useful as a supplement to standard Marine forces than they might be as outright replacements; they're far too inflexible and expensive to be fielded effectively on their own, and their lack of melee specialists and access to weaponry with a range greater than 36" is a glaring flaw (for now) as well. And while their movement is no worse than any other Marine, for reasons that totally aren't financial in origin they can't take any transports usable by standard Marines. Not Rhinos , not Drop Pods , not Land Raiders , not even the motherfucking Mastodon . They can use the Thunderhawk, but odds are you're not going to have room for it in your standard 2000 points game, and even then, it has to be carrying only Primaris Marines (and in that case, it still can't carry too many). They have a special transport called a Repulsor (which is a grav tank ), which somehow can't carry non-Primaris, but besides that they have no choice but to go footslogging.
And, of course... ---Axl Rose.....chose for himself the name Axl Rose, followed his childhood friend Izzy across the entire country to start a band, idolises Freddie Mercury, lives with a full time maid/nanny as a main companion, enjoys nothing more than costumery and elaborate set design, devoted himself to learning piano (in a hair metal/sleaze rock band, that already HAD a keyboard player...), married a supermodel and then voluntarily divorced her with surprising ease yet went into hiding for a decade after his friends/bandmate left him to his dolphins.