Re: The solo game
So, some clarification, extending from the above, and some suggestions that I hope may be constructive.
Regarding PvE:
(1) Scaling missions for the various departments, hand-in-hand with commensurate, balanced rewards. This includes both the rewards for the actual activity and any "tokens" or other such rewards. As the "level" of the mission increases-- from a backstory POV as the agent is able to accomplish more for the Syndicate, against tougher opponents (corporate or Nian), the rewards increase. From a top-down planning point of view, it would be good for the Devs to have the maximum reward in mind, so as to avoid inflation if the tree of choices is made longer.
(2) Missions for solo play are useful even for those used to groups-- the group is not always available.
(3) Group missions should have a different dynamic-- they are not just solo opponents x 3 or x5. Is there a use for certain types of specialists in the group, for example?
(4) Decide if the mission heirarchy ends on Alpha and there is a completely different one for Beta, or if one gets to a certain point in the Alpha heirarchy and then the missions diverge-- there may be an "Alpha endgame missions" path and a "proceed to Beta" path, for example.
Regarding PvP:
People have vastly different ideas of what constitutes PvP. Some think in terms of arena deathmatches. Some think in terms of conditions for victory. To some, blobbing an enemy is cheese and cowardice. To some, expecting an opponent to "fight fair" is naive.
How do you make everyone happy?
You don't.
A reasonable middle ground might be to have the potential for as many types of conflict as possible: small bot, heavy mech, solo/small group, large group. In reality, this may strain development resources. The other answer is to define the constraints upon PvP-- or the lack of constraints-- fairly clearly for players, then build the best possible game structures and venues for it, and then roll the dice and see if your community embraces it.
In my opinion, "loss" of some sort if necessary, or there is no feeling of triumph or gain when you win. However, the cost of doing PvP needs to be balanced against the amount of effort needed to get back to the PvP again.
Another factor is that sandbox games and any MMO with replenished, infinite resources of raw materials and in-game cash (e.g. from missions) will inevitably undergo inflation. If different segments of the player community do not have equal opportunity to work with inflation, the dynamic of your PvP will change drastically over the months and years also: some players will be able to afford to PvP at the new higher prices; others will not.