I disagree.

The entwiner is also giving up a weapon for 2 rounds. More if unable to see to rewield. Plus he loses some dodge and that loss of dodge overlaps with the loss of the weapon.

Plus he's picked whip and thus forgone an alternative spec.

One other issue to consider is that some people's dodge is great and others it is rubbish, even before entwine. So a giant being entwined isn't being disadvantaged much anyway, since losing Dodge isn't that significant, whereas an aerial entwining him is taking a big hit losing even half his Dodge.