There’s problems with 1 and 2 as well. Arguably they’re far more significant than the ones with Ship Legs.At this point we don't know the scope of EDO. Does it include Thargoid conflict on foot, if not then I would expect that next.
After that there are 3 prongs to attack and I would anticipate the following order.
1. Extending the variety of landable words and then their content (life/animals)
2. Extending the variety of places for on foot gameplay (Stations/planet cities etc)
3. Ship on foot gameplay
The problem with ship on foot is that they would need to do every ship and that is a lot of work or they go for selling it as an individual ship expansion and focus initially on walking around the ship and then the gameplay when there are enough ships.
For example, for planets, the next step is going to involve going from planets whose surfaces are essentially static to ones whose surface is dynamic. That has to be dealt with both in terms of the simulation of the planet’s development, and how it works actively in the ‘now’. Just for lifeless worlds it’s a huge step up in difficulty and complexity.
That’s not to say I disagree with you on there being challenges with Ship Legs. In fact I’d say there’s other more significant ones - the basic legs mechanics are more complex than for stations and planets. There’s then all the other mechanics for all the rest of the Ship Legs gameplay, all the assets, etc. It’s definitely a big undertaking.