Hello Omni,
after over 100 views w/o answer, I will try my best, though I fear my answer will not make you glad. But perhaps my post leads to the plain and simple answer you probably desire
First of all: In my humble opinion there can never be a "the perfect" deck, unless we have a very special situation described - and even then I think I would resist this term. However, with the Batariel deck, at least you can narrow down the T4(T"5") orbs and also a good half of the deck is set.
The problem to give you out the "perfect" deck is more about the T1-T3 Stage of a match, where you have several dozen good and valid ways to bring your Batariel out, depending on the difficulty, players count, playing strength, position, the well-known (or unknown) opponent faction and many more.
For the start there are 3 valid T1 colors (Green (with exceptions), red or purple), at least 6 valid T2 combinations and at least 8 valid T3 combinations - for T4 I don't even like to sketch it in theory. However, all "meta" Bataria decks meet at the end (at the "5th" Orb) again at the same color combination (order arbitrary)
2x Green
2x Purple
1x Red
But now the first exception comes up again: If played against Lost Souls as an opponent, Disenchant has no value for us, becomes rather
2x Green
2x Purple
played.
One thing all Batariel Decks usually have in common, they like to switch one green orb, after casting a Batariel. Depending on the previously played sequence, other orbs are already changed before this green orb, but to name every possible combination here would probably go beyond the scope again.
I'm just going to assume that the T4 phase of a match is the most interesting point for you, correct? Lets have a look then
The core of every Batariel Deck is obviously:
A word about Life Weaving: there will certainly be people who will tell you that Unholy Power does the same job and is even better. Resist, it's simply nonsense.
Of course, we still need healing to this core, one is mandatory, 2 is actually standard and occasionally (with cowards like me) you can see 3:
Next, and most important is an option for void manipulation, usually either
SOW OR Ofc, there can be VERY special situations where I have seen both in one deck, but this was indeed VERY special.
With the above setup, you Bata has his core mechanics and can already be very strong, but the Meta approach does not come past this 3/4 skills:
The frenetic(s) give you alot sustain, more then any heal, infect increases this even more. In addition, Infect does some damage, shares damage that otherwise only the Batariel would get (aka Meat-shield) and can put away last little things while Bata is already running to the next camp.
Disenchant does not need to be explained I guess It is worth Batariel's weight in gold
A few more words at least for the way to T4
For the T1 Phase use classical starts like
Green: Windweavers, Roots, Surge (prolly Hurricane)
Red: Nomad (usally G, sometimes R), Mine, Eruption (prolly Sunstriders and Blaster Cannon)
Purple: Either Nox/Forsaken, Motivate, Soul Splicer (g)
Common T2 choices are Phoenix (& Embalmers), Gladis (g), Vileblood, just spells or any other Unit that does help you in the certain situation.
From T3 at the latest, however, it becomes so situation-dependent that it is difficult to list all the possibilities. The classic options here would be:
If there are already 2 green, already on T3 the Bata -> usually a bit slow, but of course very safe especially in random groups or in difficult T4 camps.
Are already 2 purple available: Push the T4 with some small units with Frenetic and Infect.
Is there actually a (halfway differentiated and complete) Batariel Guide somewhere? I have never found one
EDIT: The longer I think about what needs to be mentioned, the more things come to my mind. This post truly has no claim to completeness and was only a summary of the first and most important core thoughts
