Here are several problems I do not think map makers deal with enough in terms of CTF games
CTF maps need to treat cav with a degree of prejudice. In typical CTF cavalry tend to end up being the only super stars for attacking. So the answer is to add areas near the flag that are either inaccessible to cavalry or inhospitable to them.
Examples are gatehouses, hills, and indoors.
But do not take away their role completely. Give them at least one area where they can patrol and under certain conditions, attack. An example I can give is on my map in the works.
There is a high ground and a low ground.
The low ground and high ground are only connected at two points (one near each flag) these points are guarded by gate houses of which if opened will allow horsemen to nab the flag.
Yet I allow horsemen to take advantage of several 'exit only' spots.
The entire highland is completely off limits to cav so as to preserve the infantry's offensive role in CTF
Lowlands -> Gatehouse -> Flag -> Highlands -> flag -> gatehouse -> Lowlands
setups like this give infantry their rightful place in a gamemode that would otherwise render them a 'defensive class'
The next problem that plagues CTF are ninjas. People who walk around the edge of the map away from the other players and nab the flag then run back the same way. I believe that CTF was meant to be played with more defined pathways to prevent such acts. Be it narrow streets, rough terrain, or high walls, there MUST be definition to the map's terrain.
The last problem I see is positioning of spawns. Flags should always spawn at least half as far away as the walk to the enemy's flag is.
Starting people off at the flag is a great way of encouraging chronic camping. Do not reduce the defensive advantage of a flag's base. If anything increase it. But ensure that newly spawned have to choose between defending and attacking rather than defending for awhile and then suiciding
A single peasant with a knife to confuse the friend or foe identification in a cluster should not be the deciding point in a CTF and neither should a cav on a plated charger with black armor and 4 steel shields win games. If camp off stalemates are to end then infantry must be given a vital role in attack