YES! I like that idea, adding units to specific major gods
My big concern there is power creep. The more things I add to each player, the harder it is to maintain balance with the AI. This is why I'd really prefer NOT to give level 4 units this way, if I can avoid it. Using lower-level units for this would also allow me to tweak the numbers; if a Storm god can have three Lightning Bolt units at a time, I can make Zeus' version only allow one or two. Enough to provide a nice bit of flavor, not enough to make your focus choices meaningless.
Alternately, since they'd have to be a different unit entry anyway, I can make these NOT just be a direct copy of Focus units. So maybe the Lightning Bolt is a level 3 unit for Storms gods, but ZEUS' Lightning Bolt is a bit stronger, or adds an area effect. Likewise, the Shade is a level 2, but Hades' version of it could be more like a 2.5, adding a couple extra promotions the stock version doesn't have. This'd also allow me to not be constrained to ONLY use the level 4 units for many Foci; if I want Hephaestus to have a Balance-ish unit, it doesn't have to be the level 4 Avatar unit, I can create an entirely new unit that's equivalent to a 2.5 unit but is Balance-ish in its promotions.
I'd originally intended each god to have a unique power of some kind, but that got shelved for technical reasons and because it didn't feel necessary once the Foci were in place. So this'd actually be a nice return to my earlier designs; it's just even more work to deal with, though.
Another idea I was thinking of is what about heroes baised on what foci you have? For example the death foci getting a death knight or something as a hero unit (hero anti myth promotion, spawn, and disease)
Generally, no. Heroes are going to be "named" units, directly taken from the appropriate Mythology. Greek pantheon hero units would be Hercules, Achilles, Odysseus, Theseus, Perseus, the Argos (Jason), Ajax, and Bellerophon. I'm trying to assemble similar lists of 8 for each pantheon, the Greeks were just an obvious place to start.
The key, though, is that heroes do NOT generally have "mystical" abilities like Spawn or Disease. They're men, just heroic men that are very, very good at what they do. Other than the Hero promotion (which gives anti-myth bonuses, among other things), they'll have ~3 "mundane" promotions. Achilles, for instance, has Charge, Volley, and Siege. (That's +25% vs. wounded units, vs. fortified units, and vs. cities.) They'll also have slightly higher base strengths (Achilles is a swordsman with a 13 strength instead of the default 11), to make up for the fact that their promotions are a bit specialized.
(Note: Heroes start with 30 XP, but they'll also start at level 3, meaning the game thinks they've already spent the 30 XP gaining the promotions they have. So it'd take 30 XP for them to gain an additional promotion, instead of the 10 a new unit would need. You still come out ahead.)
Now, this might not be practical. Coming up with 8 hero units for some pantheons without including any mystical abilities or non-Human heroes might not be possible, so I might have to have some of them having one unusual ability. But they'll still be "named" units.
Now, they WILL be indirectly linked to your Focus choices. The way Heroes will work is like this:
> Once you build the Heroic Epic, you'll always have at least 1 Hero. If you don't have one, the game will randomly assign you one from your pantheon. (At the moment it just assigns the Generic Hero. I intend to have the "randomly assign" part be weighted by alignment, though.)
> There are 8 "High" Events. You can't get these until you get into the Classical Era (which is AFTER you get the Heroic Epic), each only averages a 0.5% chance of happening on a given turn, you can't have any High Events within 40 turns of each other (or within 5 turns of ANY event), and each can only ever happen once (no repeats). End result, you'll have maybe three of these per game, on average. The High events have four alignment-linked options, as usual. One of those four will be to gain a specific Hero (the one thematically linked to the event); even if you're not specifically trying to pile up Heroes, you'll still average one or two extras this way.
Now, here's the catch: each High Event's chance of triggering depends on your alignment. There are eight of them, and each is linked to an alignment (L, LM, M, CM, C, CE, E, LE). If you're in the LM quadrant, then the LM event's chance is 0.75% per turn, the L and M events are 0.625%, the CM and LE events are 0.5%, the C and E events are 0.375%, and the CE event is only 0.25%. (If you're on an axis, i.e. a 0-value on the other axis, then the axial one is 0.75%, the two adjacent quadrants are 0.625%, and so on. If you're at (0,0), every High event is the same 0.5%.) So, if you've been picking chaotic Foci, then the Chaotic-aligned Hero-awarding events will be much more likely to come up than their Lawful counterparts.
Most of the events are aligned this way. The eight High events cover the eight alignments, as listed above, and range from 0.25% to 0.75%. The six Middle events are L, M, C, E, and two Neutrals; the first four go from 0.5% to 1.5% depending on your alignment, but the Neutrals are a flat 1.0% regardless (and while Mediums CAN repeat, once you get a specific Medium, that particular event won't repeat for 40 turns). The five Low events (the most common) are aligned LM, LE, CM, CE, and one Neutral, and go from 1 to 3% (with the Neutral one being a flat 2%). The Lows are only limited by the base 5-turn lockout and a 20-turn limit on repeat events, so more than half of the events you see in a typical game will be Low.
Bottom line, if you're spending most of your time in the CM quadrant, you'll see mostly Chaotic and Material-aligned events, although not EXCLUSIVELY C and M. My hope is that this'll encourage folks to try out different gods, with different alignments; take the previous Norse discussion, where the four majors each start in a different quadrant. So you'd see different events as Loki than you would as Odin; none of the events would be explicitly locked out, but the rarities would change.
Now, while the event EFFECTS aren't in-game yet, the 19 events and their alignment biases ARE (they were added two versions ago, IIRC). So as you play, you'll see "Lawful Material High Event" as the title of the event, even if the four choices are the exact same food/production/research/gold choices as always. If you were to keep track of exactly which events popped up on which turns, you'd probably see this bias in practice.