Investigator trumps Rogue in everything a Rogue does. Sure, it's 6+INT skillpoints per level, but with the inspiration ability, you can break the skillpoint cap for skills and you can do so on the fly instead of preselecting. Slightly slower Sneak Attack progression will be noticeable in the early levels, but only slightly because you're adding a list of spell buffs to make up for it and you can add inspiration to attack (and saves!). One of the Investigator Talents is "Rogue Talent", so you have the entire Rogue list and then some, only losing the advanced ones. With this package, I can't think of any reason someone would want to play a Rogue anymore.