I was using 1/72 figs on a 7' by 4' table following the 15mm movement scale laid down in the rules. Played British vs French c.1815; four brigades to a side, i.e. each side had 9-10 inf battalions, 3-4 cav regiments and 2 artillery batteries.
So, here's my comments:
#1. Poor indexing in the rules. I didn't finish my game. In fact, I came nowhere near finishing. I got barely a third of the way through to a decisive conclusion. In large part this was because I didn't understand half the subtleties of the rules, and just got bored trying to find the answers in my pdf copy.
Recommendation: Better indexing in the rules. Well, howzabout an index? A contents page is just not enough. In general I find the indexing of TFL rules systems woefully inadequate. They are one of the chief ways new players might attempt to access information. Frustrate new players and they won't come back, so this is VERY important. (This is another reason for getting that playthrough out on Youtube, ASAP please!!)
#2. Didn't like the ADC system

Sorry, my first impression is that the ADC system is just no fun. In my view this is a major, perhaps THE major, failing in the rules, especially when fielding only 4 brigades per side. It might just need some tweaking and it might well work fine at 8 brigades per side, but it doesn't seem to work in smaller battles. (And yes, I do understand about Clausewitz and battlefield friction.)
Recommendation: I would add at least one, preferably two ADCs for the CinC (divisional c/o). And if he was classed as Incomparable (or whatever it is in the - in truth often slightly annoying game jargon) then, I'd add three ADCs.
#3. Mismatch between number of skirmish bases and casualty dice and casualties. I'm sorry, but this is so counterintuitive it's just plain annoying. I have 5 skirmish bases so I get 4 dice. No. Wait a minute, is that 3 dice? Why not keep it simple and just use 5 dice?
Recommendation1: This is one of the areas where single figure casualty removal might actually work, and I'd prefer to remove single figure skirmishers rather than track casualty markers, which tend to get left behind when moving skirmishers - and skirmishers do move a lot!
Recommendation2: I would prefer counting actually numbers of skirmishers rather than bases. It doesn't take that much longer. Though I understand it is not going to be universal across all figure scales, so might not always work.
#4 Brigadiers have too little influence in the game. So, perhaps I've been influenced here by Sharp Practice, but I hate the fact that the ony function brigadiers seem to have is to remain within 30cm of their troops. It's just dull. They have no names, no characters, no influence (it seems) on the units under their command, indeed no ability even to rally off their unit's casualties (except on a Blue Moon Thursday in June after throwing a double six). This, again, was a pet peeve with the rules.
Recommendations: Look at Sharp Practice for a ruleset where this is done well.
#5 Excessive randomness on the Discipline Test. First time my vastly superior British brigade skirmish line come into contact against the far weaker opponents and they get forced to roll for discipline, and scored a three! So, a forced retreat behind their supports. As a result, they're effectively out of the battle and the brigade is screwed. Just didn't seem right. Indeed, in many places the randomness seems OTT.
Recommendations: I know this isn't easy, but I'd prefer something more attritional rather than just plain random.
OK, that's enough to be getting on with. I do have several quite positive impression but will leave that for another time. After all the positive aspects don't need further improving!