Daily system and hard cap overall is a very good thing for the players and for the game.

Why? A hard cap allows the system to be very time efficient allowing players to freely do whatever they want to do after.
Without a hard cap (uncapped system), the system has to become very time inefficient forcing players to grind for hours to progress in a timely manner and most players either do not have the want nor the time to do that, only an extreme minourity group is able to grind for hours.

Now, any pay-for-progression type of item should stay out of the game, but since non-Reboot is already ruined with this, not like adding another system would matter in the end. Reboot definitely keep this stuff out of it since it is meant for players to progress with their time only. As a whole, I do not want to see any pay-to-progress items no matter how small and insignificant it may be added to the game.

---

I do think it be a really good idea to add whole Sol Erda to the Guild Castle Weekly Reward, this especially benefits players who can only play for a few days per week and be a very good thing for the game. Even if the system has to be unlocked first somewhere in the Guild Castle Personal Research Skill Tree, get a few extra whole Sol Erda would be very nice to have, possibly Sol Erda Fragments get added to Weekly Reward as well.

---

Side note, rather than add something like Red Cards to Reboot, instead add familiar cards to Guild Castle monsters and make these cards special where they can be upgraded all the way to legendary rank instead of the cap being unique like other monster familiar cards. This will be obviously for all worlds and not exclusive to Reboot worlds, but it would allow for Reboot to get legendary ranked familiars.

To benefit newer players (and keep the playing field equal across players) make the familiar card drops immune to drop rate increasing effects.

Alternately, you could make the familiar cards only be given out from Weekly Reward and upon reveal have a chance to be Common, Rare, Epic, Unique, or Legendary at set chances for each outcome; the familiars will always be based on the monsters in the cache. Which may be better to do it this way than through traditional monster drops.

---

Short end:
~Daily quest and hard cap is very good for players and the game as a whole.
~Whole Sol Erda (what you get for achieving 1,000 Sol Erda Energy) and Sol Erda Fragments added to Guild Castle's Weekly Reward in some way.
~Do not implement any pay-for-progression type of item(s) to the game please! It may benefit the business in the short term, but really hurt the game in the long term!