To be fair, from an ability standpoint FFXIV's Egis aren't any different than FFXI's Avatars were at around Level 50. Heck Titan is ten times better a tank than any of FFXI's avatars. If they wanted more emphasis on the Egis though they could give SMNs a stance that buffs Egi stats etc. at the cost of their own. Without a stance, a straight buff to the Egis would require either a substantial increase in MP cost or recast time. It's the double edged sword of any pet class. How do you make the pets relevant without making the class as a whole OP or making the character useless without the pet summoned. As for appearance, part of that is just to give them the freedom to design the Primals without worrying about how they'll look following the SMN around. They would have to shrink the Primals if they were used as a pet or they'd dominate the screen and get in the way and Titan would look ridiculous standing barely taller than a character.