What do you guys think?

I've never been fond of Pataka and Glaive because of the high spikes in damage/magic attack.

If you want a more close range on your magic attack (which also counts for healing) then you should go for Wand/Magic Sword as long as you have a choice. Unfortunately for rank weapon you are not going to get a choice, it will be a Glaive.

i think pakatas require a few extra strength points, and are primarily useful for their high phys damage. therefore its a veno weapon primarily, and although clerics can use them well, i dont think it should be an endgame weapon. you can get def from a lot of other places. thats just my opinion.

Really, it doesn't matter which weapon you choose damage-wise. They all have the same average damage. But a pataka is simply more fun to see if you had a lucky hit or just a lame one. If you enjoy gambling with no real risk (skills always hit), why not use a pataka, also for g16? If you really want to stay g15, the defense bonuses are nice indeed, anyway.
Most of the times I have used patakas and no one has ever complained about the lack of healing quality. The difference to a glaive (the weapon type that is kind of designed for Clerics) isn't that big either.

Magic Attack +100 - 5%
Maximum Magic Attack +130 - 5%
Channelling -3% - 1%
HP: +350 - 10%
MP +310 - 9%
Strength +18~19 - 10%
Dexterity +18~19 - 10%
Magic +18~19 - 10%
Vitality +18~19 - 10%
Critical Hit Rate +1% - 9.5%
Critical Hit Rate +2% - 0.5%
Reduce Physical damage taken +2% - 5%
Atk. Level +1 - 9%
Atk. Level +2 - 1%
Def. Level +1 - 4%
Def. Level +2 - 1%

Add-ons for any N3 weapon.

I personally think people make too much of spike damage vs average damage on casters. Most our skills have a large built in range anyways. Most cleric's here are also guilty of overhealing (stacking a 7k sin with a full IH stack, for instance). Our heals also tend to find an average on their own, for instance an IH stack with 5 IHs is going to have some high end and some low end heals. And as harmful as getting a 3k wellspring heal is when you normally have 4.5k wellspring heals, its pretty sexy when you wellspring for 7k, so there are positives and negatives to spike heals but for the most part it does average out.

Also, cleric's are accused of having low dd. While that may be true in many cases, having a spike attack for 28k against a barb helps dispell those rumors

The pataka does take 56 str... 1 or 2 points more than your gear or a different magic weapon. Game breaking, I know.

I don't think you should end on a G13 weapon just to keep the pdef. As you refine your belts a +19 vit add on a N3 weapon will give you muuuch more than the +289 pdef the G13 offers, as well as providing better damage/heals from being a better weapon. But any N3 magic weapon is going to be roughly the same.

Well, I personally dislike Patakas on Cleric. Wand is the way to go for me (although due to having Venomancer as main, I chose the Glaive).

However, G16 Pataka is not that bad and it's also really pretty if you care about looks. Try for some good HP/Vit adds as it has been suggested and you'll have both better survivability and better heals.

Sticking to G13 is really silly now that NW made Raptures so much cheaper and G16 is practically free if you farm the Raptures/Badges/Mold yourself.