Rather than just have it give increased SP and HP regen, which isnt really all that useful, have it change all "City Regeneration" to "Tavern Regeneration". That way, you regenerate Action Boosts etc., and you can leave taverns without negating your SP regenerating Drink buff. That's a far more useful change to warrant the time invested in earning Silver Flame favor.

I know I often look at that mailbox in House Cannith, wishing it was just a little closer so I could go read my mail while I wait for my SP drink to finish filling my blue bar...or wishing I could use my Sprint Boost to speed things up around the Marketplace, but knowing I'd use up all my charges and not have any to use in actual quests...