I think that when you hard plumb all of the plumbing, the relative flow rates and pressures generated depend a lot on the sand filter used.
Hard plumbing from pool to pump provides the potential for a much increased flow rate, while the same from filter to pool also provides the same. Like me, it appears you have a smaller sand filter. When I upgraded to hard plumbing, I also saw a slight increase in filter PSI (a 1hp matrix going into an S180T filter), but also noted improved flow from the return - I attribute this to increased flow, increased resistance from the filter, but on balance a better flow overall. In your case you have a 1.5hp pump going into a filter of similar size, which might result in a slightly higher increase in filter PSI going from regular pool hoses to PVC. I do not think this is anything to worry about.
On vacuuming, it sounds like the vacuum hose is collapsing in on itself, and it might be time to invest in a higher quality hose - or by not having the swivel connector is causing a kink right at the head. What kind of vacuum head are you using?