I just love the 95/96 Kula - I love the graphics of that era and both of the frames were such beautiful colours and the Kula is the best/lightest Aluminum frame they make
The repaired frame is a 94, the first year the Kula was made. It's made of Easton Varilite ProGram. The 95 was a violent ice green colour and made of Easton Elan, while the 96 was a kind of mustard/gold colour and made of Easton ProGram Elite. All good tubesets, but advances were still being made at a rapid pace in aluminium tubesets at that time, so I would say the quality of the 96 frames was slightly higher than the 94.
As to whether it's rideable, I would guess it's probably stronger than it looks, but the real question is whether you would ever feel confident on it. Partly depends on what you want to use it for. Corduroyboy is more of an expert than I am, but personally I would use it for commuting/light off road and watch carefully for cracks.
The problem with repairing aluminium frames is that, unlike steel, the alloy loses so much strength in the welding process that the whole affected area needs to be heat treated to regain that strength. It seems evident from the survival of most of the original paint that the repair of your frame was not heat treated, but on the other hand it's such a bodge that it's possible the 'repair' wasn't at a high enough temperature to do much damage. Who knows?
Would also like a 96 Explosif in the green.
Might sell you the one below one day then - at least we'd save on postage.
Maybe you'll find the Lava Dome will do you, but IMO an XTR groupset would look better on the Explosif!