If you don't understand it, try it yourself. That would be the fastest way to understand why faction sucks
Your list suggests that you never (or barely) played UKF at all.
T0 HMG - you won't see many builds that gets mg before T1 upgrade. Just building one more tommy or UC gives more room for a ealry opening.
Better TD - How on the earth you think firefly is better than Jackson?
Mortar pit - Seriously...? UKF needs commander to pick normal mortar, and there is a plenty of ppl using that instead of mortar pit. What level should I be play to see opponent not countering mortar pit?
crocodile / comet - Indeed pretty decent tanks. Only if UKF didn't suffered from high pop cap.
Saxton - There is a reason for a cheap price. You get what you pay for.
HtL - Highly nerfed in terms of fire power. It's just a buy-me-a-time skill. I mean, who on the right mind would dive in to the territory that are highlighted in green? And stay for half a minute to get struct?
17 pounder - can't penerate w/o skill. Restricting building spot unlinke 88.
I literally main UKF wdym, I have been playing them more than SOV ever since I the COH2 bundle like a year ago.
Whilst you are better off getting more infantry sections/RE or ATG earlier on, it doesn't hurt to get your MG and ATG in a linear teching style unlike Soviets.If you have some form of coordination with a teammate you can benefit from getting a Vickers earlier on to solidify your hold on a sector.
I play better with FF than Jacksons, since they have extra sight with their upgrades and a way to stun enemy vehicles than might try to rush your FF if you are skilled enough to predict where they are going.The FF's amazing alpha damage can also come in clutch to finish off tanks that would otherwise live to fight another day if you have had assistance in dealing with said vehicle.And the high alpha damage being the same as the KT at vet 3(240) can also scare off less experienced opponents.
I just don't see any redeeming things about the Jackson, it seems like the least reliable TD ouf the allied TDs in my experience.
Mortar pit and 17pounder are situational as I have already stated I believe, if the enemy already has tools like massed mortars or static/rocket arty they're not going to last very long despite having brace.But they can also be instrumental in holding the line against heavy TDs or OST support weapon spammers without MHTs.
The Sexton more than pays off it's low price if it survives for long enough to rack up damage, I had like 60+ kills and 20k DMG the first time I used Royal Arty with only 2 Sextons for an entire match, which lasted for about 40mins-1h.
I play top 200 premade 3v3 and still see people walk into the HtL territory zones on the daily.It's a useful tool to help you if your opponent dives your armor with his own, if you're getting pushed across the entire map, or just to keep a stranglehold on the VP points, forcing your enemy to bleed which is all the VP gamemode is about.