Perhaps a second look is in order at PGL's abilities then.

PGL Abl. 1 "Second Wind" - A pretty potent self cure

PGL Abl. 3 "Taunt" - Focus attacks on you

PGL Abl. 4 "Featherfoot" - Boost EVA and returns MP when you do evade. Not much use unless your the one being attacked

PGL Abl. 6 - Uses MP to boost DEF. Also does nothing unless your the one being attacked

I would count all those as tanking abilities. I don't know if the intent behind these abilities is main tanking or more situational (i.e. off tanking or positioning mobs for a FFXI style Sneak Attack + Trick Attack on a main tank). Whatever the reasoning behind these abilities it seems clear that PGL is meant to be hit by the mobs at least some of the time.

MNK Abl. 1 - Temporary increase in attack speed to generate TP faster

MNK Abl. 2 - Adds kick attacks. Remember the 1:1:0.75 ratio for emnity, auto attacks might not seem like much but it adds up over time.

MNK Abl. 4 - Burns MP to boost EVA. Once again of no use unless your being targeted by the mob.

The monk abilities seem to marginally boost tanking abilities on their face, we'll have to wait for the patch to see of how much use they actually are. It is my feeling that each class will eventually have 2 jobs they can become and PGL's second might be more of a tank (Ninja anyone?)