Back in the early 90's the world 1/300 modern championships in Derby changed from the usual "meeting engagement, pick your own XXX points army from the army lists book" to a scenario-based model where you were say trying to pull your HQ trucks and SAMs off from an invading force, always NATO and Soviet (so your old Kuwaiti (say) army was now relegated to the shelf). I gave up competing in that period then as it was not really fun since I liked to play the old way.
So I dropped moderns and then I went for the WRG Ancients, 7th edition rules then DBM in 15mm. Didnt do as well as Ancients were a
huge competition taking the main central auditorium at the snooker centre whereas Modern 1/300 took up a side room. But no dealing with weird scenarios where your VP came from safely exiting fuel trucks and HQ trailers off the side of the map before Ivan stomped them flat, and no requirement to provide both a Warpact and a NATO army as well either. And no need to buy and paint up those weird "B" vehicles which were no use other than at Derby, (maybe the organisers were in cahoots with the model sellers
!)
I recollect that the last year that I played Moderns, you had to provide a defensive and a meeter list (same army) - the start of thier "scenario based" fights. Got blitzed as UK defending vs
Tanzanians, who had a cloud of very fast and very cheap APCS and a few scorpions who were on me almost instantly, charged through the pre-laid defensive mines and got stuck in, my Milans and very few scorpions took a toll but then they were in bayonetting everyone... I was relying on my expensive minelet equipped FH-70s to make the main defensive belt but by the time those fell, the Tanzanian racing cars were
well past the pregame plotted impact zones so the minelets dropped into the empty space behind the hordes!. Nightmare.
Way back in the early 70s I had played at the UK championships in 1/300 using WRG WW2 rules, and in those early days there ware
no army lists. Someone for example turned up with just a few on-map FOO parties backed by an off-map
host of artillery. A very cheap and easy to paint army
!. He used the few jeep FOOs to take the objectives while the arty plastered the approaches with regimental level stonks. The very next year, they introduced an army list booklet!. That coincidentally nixed my Soviet army of all IS-2s with a few maxim HMG teams and a couple of 120mm mortars used for smoke, since the army list had a rule like "2 medium tank coys are required to be bought in order to buy a heavy tank coy"
The absolute easiest to paint and by far the cheapest competition army I ever came across was the opponent one of our guys who was playing some sort of "pixies and fairies" rules though (early edition warhammer??). Probably in the 1980s. His opponent's army was composed just
one (1)
invisilble dragon loaded up with magic spells which came to the total of points allowed. I think the fantasy section introduced army lists with a "core" force of troops on the map after that initial year!