I personally think every single top laner should take TP. It just makes sense to be able to respond to your team's plays across the map, instead of wasting it on some 1v1 spell that can win you lane, but lose you the game.
League is a team focused game to me, and taking Ignite top lane shows me you want to make flashy plays and feel good that you can "outplay" someone with a summoner spell advantage. Teleport adds to the team, not to your ego.
Depends. I'd take ignite on snowballing lane bullies with mobility like Riven, Pantheon, Quinn, etc. but play TP on safe teamfight oriented champs like Cho'Gath.
Nay unless you have the mobility in your kit to compensate for not running Teleport AS WELL AS a lane bully kit that you can use in combination with Ignite to both snowball yourself and shut down your lane opponent.
tfw the adc takes barrier over heal tfw mid takes ignite over exhaust when they're a mage against Zed tfw support gets ignite (some exceptions, but hey) tfw jungler doesn't have smite
As with most things, it's situational.
For some tops you practically NEED to bring ignite. 
Other times it's a very even matchup and ignite/exhuast might be the resource you need to keep your opponent from snowballing off you.
Other times, you're royally boned if you didn't take TP and the enemy did. They get a free back and you don't. Which could cost you a lot if they have a lot of push. It could even be this way if you decide to use your TP for the team.... you'd be miles behind if your play doesn't work out and you've got to shuffle back up top to find you have no tower to protect you any longer.
At the end of the day it's what makes you feel more comfortable. Sometimes I take TP mid if I'm okay with the matchup and we need to be able to have the map presence for an enemy who is renown for split push.
it all depends. on someone like darius, i'd take ignite. On someone like irelia, id take tp.
why not take both! flash is for the weak!
Goes 3-0 Darius, gets fed. Looks down bot lane and see's our ADC and Support pushed up against our Turret, enemy ADC and Support poking/trying to siege. I ping omw. I TP to a ward in the bush. I'm BEHIND the enemy bot lane. I target ADC. I engage. Our ADC and Support stays under our turret cleaning minions. I'm in a 1 v 2 as Darius. I'm already there, gotta fight. Enemy jungler comes, ganks, saves their ADC. Jungler and support proceed to turret dive and get a triple kill.
TP is nice for making plays or getting your team to make plays. In low elo you're just a likely to TP into a situation where you cost your team the game bc you'd have been better off pushing one lane then TP'ing to another, split pushing. Ignite is a whimsical thing top lane, I'd find exhaust to be more useful in many causes. Some champs have MS steroids that aid them in returning to lane. Ideally I feel the same way, I look at the enemy team in load screen, don't see a TP, I might think ( Oh wow look at these noobs no TP on top laner ) And we may very well end up losing that match. Badly.
Fun thing about this game is it is both about how you play and how you make plays with your team. LCS plays work because of the level of coordination teams have and the fact it's not a duo and 3 randoms together (at best) or just 5 randoms (typical) trying to get everyone to be on the same page. If YOU can use TP for you own purposes, use it. Just don't bring TP with the mandatory assumption the second anyone on your team see's your TP casting they will pile in and capatlize on your awesome play. They might. But you should not count on it. Also I've seen mid laners take barrier and heal over ignite. I've been on a team before where neither myself nor anyone on the team even had ignite. And we still won.
Things happen. Different things work in different elos. You might be able to pull yourself up out of bronze using weird things like Ignite top lane or Lindry's Torment Mundo, or ignite smite jungler. Or , Clairvoyance might be the solution. You can ping all day, , you can ward all day, you can ask Zed to back away all day. In lower elo you just can't depend on your team. Sometimes ressing D to instantly reveal all the champs is the HANDICAP your team needs. As you climb elo and rank, you have less need for such tactics, and you have more incentive to cooperate, thus that's why things work in one tier but won't in another. What works in Gold WON'T work in Bronze. What "works" in Bronze (is that possible) won't work in Gold. Also, words.
Most of the time, it's best to take 
to top lane, especially if you're going tanky top. To me, only champs who can get to their lanes faster than others like 
, or someone who can already help other lanes with their own ability like 
, are ideal to take 
top lane.
Ignite is fine to bring to the top lane if you can get a great lead off of snowball. And TP in solo queue isn't even used for the team most of the time. It's used so you don't miss any CS so it's insurance for any weak laners/strong late game champions that might fall behind early.
Ignite is really only useful imo if you can use it to snowball your lane. If you don't feel you have to skill/knowledge to be able to get kills really early, ignite feels like a waste to me. Taking TP will give you a lot more pressure late game, allowing you to split push and make laning easier early game allowing you to back more. Honestly, it is just trade offs. TP is taken in higher levels of play because the players are more focused on the team aspect of the game and know how to make use of if.
If you mean to snowball 
etc. and are confident with that champion, then yes I would recommend taking it. If you can stomp your lane so hard that their jungle has to keep babysitting their top, while your jungler is helping the other lanes then you effectively carried that game. By taking complete control of your lane allows you to take control of that side of their jungle, and easily roam. It's a pretty effective strategy, and is how I have been playing lately.
