What Empower spell doesn't affect are any skill checks, saving throw checks, and other checks. If a spell makes a variable ammount of saving throw bonus, then the saving throw bonus is subject to empower. The description says, all numeric, variable effects. It doesn't really matter whether the effect is a damage, healing, saving throw bonus, temporary hitpoints, attack bonus or duration of the effects from AOE that spell creates.
Empower Spell [Metamagic]
Benefit: All variable, numeric effects of an empowered spell are increased by one-half. An empowered spell deals half again as much damage as normal, cures half again as many hit points, affects half again as many targets, etc., as appropriate. Saving throws and opposed rolls (such as the one the character makes when the character casts dispel magic) are not affected. Spells without random variables are not affected. An empowered spell uses up a spell slot two levels higher than the spell’s actual level.
This is the description see that damage, healing, and targets are definite; while opposed rolls (checks) and saving throws are rejected. What is left is grey area, it can be argued back and forth.
Im not so convinced by this argument. This "creature" is not described anywhere outside of the spell. Its not like the Shambler spell that defines the creation of 1d4()+something shambler mounds where their damage is definitely not a subject to a metamagic. 3.0 evard tentacles on the other hand? I would say that they do.
3.0 provides full creature statistics for its tentacles including saving throws, hit points, strength, base damage, and the types of spell immunity. It is unlikely that the 1d6 meant anything other than part of the description of the creature (especially given how the description reminds you parenthetically that the strength bonus (+4) is to be applied). However given that this value is within the spell description and it doesn't meet the automatic in or automatic out criteria it is within the grey area, and as such is debatable.
1) The Krits argument is off. Duration of the spell effects != duration of the spell. (and this itself should be reason to revisit my edit back in 2012)
Your edit was to delete a comment. By not wanting your edit "reverted" again did you want to have the comment completely removed, or to have some explanation so that it would not get readded?
2) the way its written in the spell description makes it to be the "numeric, variable effect"
Which means when going through a spell description if a numeric expression is encountered and the evaluation of that expression is not a constant then it would be a "numeric, variable effect." However, later sentences give indication as to what is automatically qualified and disqualified producing the grey area where numeric, variable effects may be questioned as to whether or not they should be increased.
3) to your argument with tentacles to be a creatures: each of these spells, magic missile, color spray, cloud of bewilderment, evards black tentacles is creating an object and its this object who is making the damage/effect. No difference between these and we know that damage of the missiles created by the Magic Missile spell are affected.
If you argue that way then you would have dismissed the way I argued the 3.5 tentacles. No, the 3.0 tentacle's damage was ruled as part of the normal attack due to the way the spell presented it.