There doesn't seem to be a sub-forum for feedback on the rules (just rules discussion and other feedback), so I'll assume this goes here... These are my notes from my first pass through the rulebook, before actually playing.
Positive
2E - Overall, I like the broad strokes of the new system, with some key highlights below
Actions - The new system is vastly superior.
Senses - This is a much needed change. Not having this has caused problems in our games.
Tactics - It's great to have this formalized to prevent a lot of "but I actually meant I was doing ..." moments.
Constructive
Ready - Seems like this should also allow preparing activities that consist of a single action, but it doesn't appear to be the case.
Polymorph - It seems weird that a short duration polymorph would completely dispel an unlimited duration Baleful Polymorph effect, rather than just suppress it temporarily.
Storm Druid Order - Creating dangerous unnatural weather patterns is anathema, but it seems like some spells/powers that do this would be designed for this order (e.g. Storm of Vengeance).
Skill Feats - Some of these, e.g. Survey Wildlife, are things that most GMs would allow you to do without having a feat.
Poor-quality Items - If it can't be sold, then how can it be bought?
Familiars - There appears to be a lack of beneficial Master Abilities for Sorcerers, especially since they can pick Improved Familiar.
Reload - This would probably be clearer as a specific activity that involves Interact actions.
GM guidance - I'd like to see more guidance for entries that say "the GM decides"
Clarification
Doubling Damage - What if the effect is an attack roll that allows a save?
Resistance - It sounds like this implies that for any resistance other than "all", each packet of damage should not have resistance applied separately, but it's unclear.
Heal - It's unclear whether "reduces the amount of healing to ... your modifier" under the 3-action version overrides the "increases by 1d8" from Heightened. Is Heal+1 with 3 actions supposed to still only heal for your modifier, or modifier+1d8? Similar issue when combined with Healer's Blessing.
Enervated - Shouldn't this also lower your DCs that include proficiency?
Confusion - Does "attack" here mean Strike, or does it mean harm to the best of your ability, including casting attack spell, or even non-attack spells.
Swift Dispel - It's unclear whether this actually spends the spell slot. It seems like it should, but as written it sounds like it doesn't, because of it's a dependent action.
Editing
General - Add an icon for activities.
Playing the Game - PDF bookmark hierarchy might be incorrect here.
Critical Hit Damage - This sidebar has an extra bit that isn't included in the primary "Doubling Damage" section.
Quick Recognition - "Recognize a Spell feat" -> "Recognize Spell feat".
Playing the Game - This chapter would benefit from being earlier in the book. It's very confusing trying to understand the earlier sections without this information.
Failure and Critical Failure - "If an action or activity does not specify a critical failure effect ..." is repeated twice.
Feats - Some feats, like Fleet, have the "Skill" trait, but aren't related to a skill, and are under "non-skill feats" in the table.
Prismatic Wall - "prismatic wall has seven different colors, each with the effect of a 5th-level chromatic wall spell of that color", but 5th level chromatic wall doesn't have seven different colors.
Survey Wildlife - This has a single action icon, but it takes 10 minutes.
