Hi MJ82. I think it is quite wide, but still not to be discounted as an 'influence'. My take on orbs is that a very close orb makes for a more compelling and unavoidable tie between the planets - like they just can't leave each other alone, especially with the hard aspects. But the wider aspects are weaker and there is more choice of whether or not to cultivate the connection. Some people use 10 degree orbs, especially for a hard major aspect from the Sun. But I would never consider anything beyond 8 degrees in this case.
When I say that water is probably the underdog I am getting Jungian. Jung noted that the thinking (air) and feeling (water) functions are opposite ways of evaluating experience, and that they cannot be used simultaneously, though one can be used to back up the other. People are inclined to develop one of these functions at the expense of the other, and the less developed function tends to behave more unconsciously, immaturely and unpredictably.
Because you have important points in both air and water, you cannot really get away with just relying on one element in your adaption to life, because if you do the planets in the denied element will be very suppressed. Your strong air means that you have probably developed your thinking function at the expense of feeling, and so feeling is the underdog. But because your Sun and Jupiter are in water, you have to also develop your feeling function in order to express and fulfil the powers and urges symbolised by these planets. Without Sun and Jupiter you may lack the confidence and spontaneity to follow your own special unique destiny.
When your parents divorced I'm guessing that you saw less of your father, because like waybread said above, Neptune erodes and dissolves. The Sun is often projected onto the father as a role model for one's emerging solar energy, and so when the aspect became exact, your connection to your solar centre perhaps dissolved to some extent. With Sun in Pisces, and that square to Neptune natally, you probably already experienced him as somehow difficult to grasp, elusive, weak or absent. Of course he may have had many positive Piscean qualities too.
Your work with visual art is probably giving your Sun in Pisces a really good vehicle for expression. Pisces Suns often have to swim in the waters of collective feeling in order to find some sense of selfhood. With Uranus culminating and Aquarius rising, you'll probably need to express revolutionary ideas through your work as well, at least some of the time - ideas that promote humanitarian ideals possibly.
I think Neptune's house position is much more important than its sign position. The 11th house is the natural house of Uranus and Aquarius, and so this adds to the importance of your ideals and ideas, and probably of identifying with groups that share them.
With Neptune in Sagittarius you are part of a generation that will experience idealism and disillusionment around issues of faith, religion and the meaning of life. So the individual expression of your Solar energy will perhaps be a vehicle for this generational process, helping others who are less in touch with collective feeling and imagination to experience it.
I think your 8th house emphasis, Jupiter in Scorpio and strong in its natural house, plus the very strong trine from Mercury to Pluto will draw you into the hidden side of yourself and others, and I'm sure this will influence your work also. the intimate encounters and self-communion that will draw out that which is hidden from consciousness may feel daunting with Mars, Saturn and Pluto all in the 8th, but I would say its very important for you to face any fears and slowly develop your capacity for intimacy. We're back to the need for water/feeling again here.
You mention that you feel you need more earth - Saturn largely reflects your endowment of discipline, realism and focus. Saturn is in your 8th house so you may need to check sometimes that your ambitions are not a way of avoiding experiencing intense, transformative feelings, or that your industriousness is not bogged down in real or imaginary power issues.
Mars is your potency and healthy aggression to pursue your goals, while Pluto has much passion, insight and stamina. The Moon is obviously always an important planet to satisfy for our physical and emotional well-being. These planets may also need 'rescuing' from your 8th house.
You were probably given messages when young that its not a good idea to show raw emotion and passion. I would guess that after your father left there was much unexpressed anger and bitterness in your Mother, that you sensed and didn't know how to handle. The Uranus exactly conjunct MC suggests that maybe she felt trapped by having to bring you up more on her own, and this perhaps added to her frustration.
But this is speculation. Please disregard it if it doesn't resonate with you.