My girlfriend is playing Dark Souls

My girlfriend has become addicted to Dark Souls. This was completely unexpected, since she's not really a gamer and she's certainly not very skilled. The rush of prevailing against overwhelming odds through sheer force of will seems to appeal to her, though. She's about ready to fight the Gargoyles.

I've encouraged her to experiment with the various weapons that she's picked up during her initial run through the Burg and environs, and she seems to have settled on the Estoc as her favorite weapon. I taught her how to get the Drake Sword so that's what she's using now, but soon I'm going to have to teach her how the upgrade system works so that she can choose where to invest her titanite and souls.

I'm glad she's found a weapon that she likes. Getting to know your weapons is one of the funner parts of Dark Souls. I'm concerned, however, that the Estoc won't be a good choice for her in the long run. It excels in the Burg and the Parish where you're fighting lots of low-HP, low-poise enemies at once, and the ability to poke from behind a shield or use the wide R2 can be really useful. But it doesn't scale well at all: at 16 str and 40 dex its AR is 330, against 380 for the BSS and Winged Spear, 390 for the Falchion, and 420 for the Uchi, none of which have appreciably slower swing speeds. It's obviously not a candidate for elemental upgrading either, and the consensus seems to be that the Falchion is without a doubt the best spellsword.

I'm concerned that the Estoc might turn into a handicap once she gets to Quelaag or Sen's. My preferred weapons are halberds and greatswords, so I don't have any experience with how quick, weak weapons fare in PvE. Because of the way damage resistance works, though, it seems like they would be disproportionately effected by high endgame resistances (since resistances take a flat amount off of each swing, rather than a percentage).

Obviously a skilled player can beat Dark Souls with any weapon, but she's not a skilled player and I wouldn't want her to put herself at too much of a disadvantage. Should I gently steer her towards another weapon, or will the Estoc not be that big of a problem if she sticks with it?