Modifiying pa 2 way cabinet

[Bull]

1 year ago I bought a pair of pa speakers brand new costing £300 pair.I'm really happy with the bass response,and cabinet,but the rest, midrange and treble sounds cheap and horrible.
The cabinets are not made by any manufactor,just bought in a dj shop.
The drivers are 1x Eminence Beta 15,150w rms,8 0hm,4mm x max,35hz-4 khz,38 oz magnet,kapton coil former,2 inch voice coil.

1x CTS KSN1142 powerline piezo horn driver protected to 400w.
1x 15 inch x 5 inch ABS plastic horn

The cabinet is made of 18mm plywood and has a centre cross brace,and batterns which are glued and screwed.

It is covered in tough professional felt carpet,with metal corners,and plastic ressed handles,and dual 1/4 inch jacks on the back mounted in a plastic round recessed plate.
The baffle board is made of 1 inch thick particle board,and 4,3 inch round holes in the baffle instead of ports.The cabinet is also trapazoid shape.

The bad points are 22 gauge,OFC special cable,high temperature cable rated 105 o C.The cable is small but why have the manufactor used high temperture, highly flexible cable.
Could I replace it with 12 gauge ofc for the bass,16 gauge ofc for the treble.Also the connections to the bass driver and treble are spade terminals,no direct soldering.
Also there is no wadding whatsoever on the back panel,so maybe if i should add a 1 inch thick fibreglass panel on each rear panel?

Last but not least I could replace the piezo tweeters with cheap compression drivers and crossovers,say Eminence APT50 comp drivers and Eminence 2 way crossovers.Is it worth doing this,or should i just add wadding to the back panel,and upgrade the internal wire.I can't really add ports to the holes in the baffle,because i don't know if it would tune it correctly.