I'm coming late to this thread, so there will probably be some overlap. But I think I have a novel approach.
Don asked the question (if I'm summarizing fairly) whether the primary 'end' of life can ever be described as other than the highest good.
First, a quote from Tony Kushner's excellent script in the film Lincoln:
QuoteThaddeus Stevens:
You know that the inner compass that should direct the soul toward justice has ossified in white men and women, North and South, unto utter uselessness through tolerating the evil of slavery.
Lincoln:
A compass, I learnt when I was surveying, it'll point you True North from where you are standing, but it's got no advice about the swamps and deserts and chasms you'll encounter along the way. If in pursuit of your destination you plunge ahead, heedless of obstacles, and achieve nothing more than to sink in a swamp, what's the use of knowing True North?
Now, that quote has problems (ahem...True North?), but the analogy of the compass doesn't seem half bad here.
An Epicurean might well say that the inner compass furnished by nature will–not should, but will–direct the soul toward pleasure. The compass is not normative, it is descriptive–even the inner compass of infants can be inferred to point toward pleasure.
If an individual finds themselves repeatedly veering toward pain and anxiety, it is not because their compass doesn't work–it is because they are ignoring it, or have conditioned themselves to use it improperly, or they've been given misleading directions or a faulty map (for example, they've been raised to understand that "real pleasure" is in following Christ, or whatever). What they need is not a moral chastising, but simply better training. They need to consult their compass, not someone else's poor directions.
The direction of pain isn't evil, or the "greatest bad", any more than South is bad. But it's not the direction we're driven toward by instinct, and upon reflection we'll probably find it's not the direction we really want to be going anyway. Nature has not furnished us a compass that points toward pain.
Even in consulting our compass, furnished by nature to point toward pleasure, we won't always be able to travel there in a straight line. Sometimes we have to traverse in the direction of pain to find a route that goes ultimately toward pleasure; a route that answers the cry of the inner compass.
So perhaps instead of saying "life is the highest good", or "pleasure is the highest good in life", we should be saying "pleasure is the magnetic North of life's compass".