Without seeing the tree in person it is hard to make informed advice.
1. I usually start assessing any tree at the roots. As Pearcy says, nebari is very important in most bonsai but you do have to work with whatever you have. Look for the side that shows the best spread of strong roots.
2. is the trunk. Look for the side and angle which gives best flow. Yours is rather straight but we can change that in several ways if necessary.
3. Branching. Most styles require well spaced branches, some toward the front and sides, a few at the rear to give depth. Look for a side of the tree that has best branching remembering that some can be removed to make space.
4. Features: Look for anything that stands out. Features can be dead wood, scars, really nice bends in trunk or branches, roots, etc. Anything that looks good can be a feature.
5. Faults: Look for things you don't want to show. Sometimes scars or wounds can be faults, reverse taper, bar branching, thick parts in the upper tree, etc can be faults.
Now look for one side of the tree that shows off as many good parts that you have identified and hides as many faults as possible. Sometimes you may need to chose slightly less attractive roots to have good branching and better trunk line and show a good feature or less than best trunk shape to get better roots and branches. How important various aspects are can depend on the species - nebari is less important than trunk in juniper, nebari is far more important in maples and branches can be regrown easily so branching has less importance.
From what I can see of your pine you will probably need to chop but may not need to cut as low as Pearcy has shown. Maybe one of the next cluster of branches could be a viable new leader? Especially as you have expressed a desire for a larger tree. Much will depend on how many shoots are on those ones and how much bare wood. It may also be possible to use one of the upper branches but all other thick branches must go from that cluster soon. Some shari or jins may be able to disguise any reverse taper there and convert that fault to a feature. Pines are relatively flexible so even quite thick wood can be bent so it may be possible to make some bends in your trunk.
Pines are reluctant to bud on older wood so you will need to cut back to smaller healthy shoots.
having a go at putting some bends in the trunk and giving it a serious haircut and style the same day as the trunk chop?
You should be able to do pruning, trimming and bending all at the same time. Many growers prefer not to do styling and repotting close together for fear of weakening the tree too much but above ground work only is considered safe.
As this pine has not been pruned much I would suggest pruning all branches back hard some time soon. Always cut to leave 4-6 healthy needles or a healthy side shoot or the branch will probably die. Growth has now finished so you probably won't see much movement until spring. I can cut pines hard any time of year but resulting shoots tend to vary depending on timing. Pines pruned from late summer through to spring usually grow larger new shoots the following spring. Pines pruned in later spring and early summer quickly grow many smaller new shoots during summer. Feed pines well all year round to get best budding and regrowth after hard pruning.
