I dunno about removing the mana cost to "primary" skills. I'm not sure if they're even meant to be "primary" skills like spirit/fury/hatred generators. They're just used that way because they cost the least mana and can be spammed.
I think I'd still like to have WD be different from the other classes in this sense. The low mana skills like dart can still be spammed, but I think with the mana regen idea I had, one of the goals of witch doctor would be to achieve particular break points in your build where the higher the mana regen you are able to achieve, the more powerful your "primary" spam skill will be able to be. (e.g. being able to switch out your primary from darts, to say, firebats or spirit barrage or something).
I don't think stronger passives for pets is that necessary, imo. Resistances already add to pet defense, and I think they're going to make it so that vitality also adds to pet HP. Just buff the current pet passives too and we're almost there.
Darts being spammable isnt the problem, it is being able to regenerate mana fast enough to use better skills before packs of mobs overwhelm you. Just using basic attacks, you are penalized with mana costs, so it delays using other skills longer than it is necessary. This limits build diversity as you need to prepare for being low on mana and still need to either do damage or have a skill/spell help delays mobs until mana recovers.
For some reason they put a penalty in place for WD for using simple basic attacks. Unless you are using VQ, you either need to wait longer for mana to regen using primary skills or not use anything at all. WD have no free attacks. Darts should be free of mana costs, the same as magic missle is free of arcane cost. All classes should have some basic skills that costs no mana, arcane, fury, hatred etc. As it is now, only the WD has a resource draining penalty on simple attacks.
Maybe if they overall cost of stronger WD spells was lowered it would be a non issue, but attaching high mana cost to most WD spells, mana drain on primary skills and the lack of good mana regen is the biggest issues with WDs and their mana issues. Ive played WD for 100's of hours and I dont see how removing the mana costs from Darts, Corpse Spiders and Firebomb would overpower them in any way.
Pets do benefit from resists, but they need a lot of help without going overboard. By reworking two different passives one for pets users and one for dot/poison users, it would allow them to buff those lines of skills while penalizing the other path. If they buff both without putting some restrictions, a hybrid build that uses strong pets with strong poison/dots will be overpowered and then they will have to start nerfing the class. I would rather than take their time and think things through to tune it properly, instead of tossing in a lot of huge changes and then nerf the skills because they are overpowered.
I agree and want WD to play differently than other classes, but they need a lot more help than increasing mana regen and buffing pet passives slightly. I guess we will find out soon enough what they have in mind for WD and then we can see the direction they want the class to go.