Full Idea
Most of Bentham's 'dimensions' of pleasure refer to further pleasures, or are irrelevant to the pleasure; we are left with intensity and duration as the characteristics on which depend the value of a pleasure qua pleasure, and there is nothing to add.
Clarification
'Qua' means 'purely as'
Gist of Idea
Of Bentham's 'dimensions' of pleasure, only intensity and duration matter
Source
comment on Jeremy Bentham (Intro to Principles of Morals and Legislation [1789]) by W. David Ross - The Right and the Good §VI
Book Reference
Ross,W.David: 'The Right and the Good' [OUP 1930], p.144
A Reaction
I agree. When Bentham produces his list he seems to be trying to add a bogus enrichment to what is really a rather crude and basic notion of the aim of life. Your simple hedonist appears to only desire high intensity and long duration.