Not trying to hijack the OPs thread, I'm just currently making a druid who is also focuses on animal companions. So I'll add my ideas in and see what others think.
I'm about to start a ebberon setting druid, for the age of wyrms campaign. So please no spoilers.
I originally designed a progression for a druid focused on wild shaping with warshaper/natures warrior, but decided to go back to mostly druid levels because sofar nobody in the group wants to play a healer.
Was thinking of taking Skill focus(handle animal) and Beast Totem(ECS) as my 1st level feat + human bonus feat...at 3rd I'll take Natural spell, and at 6th I'll take a level of beastmaster and the Totem Companion(ECS) feat. That will give me an effective druid level of 9th and allow me to have a Displacer beast companion with 3rd level companion bonuses.
at 9th I was planning to take companion spellbound so I can share spells at 30ft and by then I'll have a decent list of buff spells to share. The cool thing about the displacer beast is that even though its a magical beast, I can still cast animal based spells on it, as per the totem companion feat.
Seemed like a pretty sweet concept to me, to have an large 8HD pet with 3 attacks 10ft reach, 50% miss chance, and evasion at 6th level. It also has a 5 int and can SPEAK common. The alignment says usually lawful evil instead of -always- like most other monsters, so Im not sure if I can attract 1 with a non-evil alignment, I am hopeing so.
Comparing it to some of the dire animals it does less damage, but gets more attacks and has way more surviveability imo. Plus it can actually communicate with the group by speaking which I think would add a fun RP dynamic as the displacer beast can hurl his own insults at people for being dumb
1 thing to note is that the Totem companion feat has ambiguous wording...it says there is a minimum level requirement, but it's not listed as 'minimum character level'...Instead it just shows the chart that refers to effective druid level and references the chart in the PHB. So the way I read it is effective druid level will qualify you to take the feat at lvl 6, instead of waiting to lvl 9 because of the beastmaster bonus.
No word yet from the DM if he will let natural bond give effective bonuses or not, but I doubt it. I haven't written the character up for him yet to look at and approve, but sofar he said he didn't have a problem with me getting a displacer beast companion.