The Meta- am I understanding this correctly? (warning, wall of text/doom)

Been thinking this through to try and understand it better (as to why what goes where) and since I don't know what the meta really is, I'm just going to post what I think makes sense and hopefully someone can tell me right/wrong and why? (all is assumed as playing 5v5 even skill level summoner rift)

5 players on each team with a plethora of champions, masteries, runes, and spells to choose from for variety of playstyle. There are also 6 distinct locations- home base, enemy base, top lane, mid lane, bottom lane, jungle.

No one needs to set up for either base as that will happen from a series of event because bases are destroyed to win. That leaves the 3 lanes and jungle. But there are 5 players. Map analyzing shows that there are two "epic" monsters in the jungle - Baron and Dragon. Baron is near top lane and is much stronger than Dragon who is near bottom lane meaning Baron won't usually be stolen until end game, again referring to the issue of no player needs to preset for a base. So bottom lane has a dragon who gives massive gold every so often to the last hitter of whatever team does last hit. Meaning 2 players on bottom lane. But who is to keep an eye out in case someone goes near Dragon? Need jungler. Then you have 2 players and 2 lanes, and its impossible to have an uncovered ground which means the meta of ------- 1 top, 1 mid, 1 jungle, 2 bottom is indeed correct.

The Jungler: The jungle is about the size of 2 lanes sitting side by side, so the jungler needs to be mobile and hard hitting- characters such as Evelynn and Kassadin, Fiddlesticks and Fizz would be there. They also need a good deal of survivability because the monsters do start out as hard to kill and end up being one-shottable (in theory). Smite will assist in quickly taking down monsters, and ghost will help movement speed. But jungle is perpendicular to all 3 lanes with easy access to either half of the lane. That means they can gank as well, right? Jungler probably still needs ghost, but may need heal so it becomes preference- heal is for staying in a fight if necessary or helping get CS early. Jungler should therefore level quickly and essentially become a bruiser (correct term?) that is equal parts tanky and damage. This means the Jungler has to be a highly mobile, highly dangerous champion- Fizz or Evelynn are therefore preferable and items that give armor and either AD or AP are essential.

The Bottom Lane: Seeing as we have allocated 2 players to protect the epic monster "Dragon" to this lane, that gives more leeway. However, experience in this lane is now divided by 2, as is CS from minions. But that won't do, then the jungler will scale X2 of bottom lane and will , again in theory, be able to solo the two champions or even it out- and there are 2 other players on the other team. That means you need either a Carry and Support or a pair of Tanks so they won't get wiped off the lane. Vayne and Sona might work here, as would a pair like Cho'gath and Taric. To make the CS/Exp meaningful however, these 2 need to become either self-sustaining (dual tanks) or one needs to scale higher than the other who will then become the proverbial horse of the cavalry(DPS/Support). Either one will keep Dragon safe. But you also need lane pressure to make sure it is easier to save said mob, hence jungler. But what if there is no jungler nearby, or they are occupied? The combination of summoner spells should be Heal, Barrier, Exhaust, and Ignite. Equal parts safety and push. Items should be either a combination of Bruiser items or Push-Combo.

The Top Lane: One player in this location who is near Baron. Baron can save itself though. That means you only need to ward one location to make sure you won't get ganked, which isn't an issue in bottom since they are covered from the Jungler and if more than that is sent then other lanes or zones can be pushed with ease. This means you need sustain in the lane so that you can scale appropriately for late game, having no worries for early phases. More than likely, this will be a tank character. I don't pretend to understand much of this lane, so as far as I know this will be right. Ideal spells are Heal/Ignite or Ghost/Barrier, that way its possible to "dive a tower" for a kill that way lane can be pushed or sustained as necessary. Ideal characters are one's like Leona or Volibear. Items must be built so that player can survive being hit hardcore as they must remain focused on pushing a lane altogether and that means tanking a tower as long as possible in later phases.

The Middle Lane: Last player allocated here. There is no safe zone besides the one where your tower stands. That means if a tower falls, you must fall with it- in the sense that you don't stick around and get ganked, but instead run to the next tower and continue laning that way. You will have a great deal of CS and Experience being alone in the most dangerous location on the map. To improve survivability, you will probably need damage. I say damage because being in the middle of the map means you share one of the junglers key roles- Ganking other lanes. So you will be a caster, preferably ranged because you will be the squishiest character by a large margin on the team. Characters for AP would be Veigar or Ahri( for the quickly scaling power), AD would be Jinx or Ashe( because they can assist other lanes without leaving via their ultimate). Ideal spells are Teleport and Ignite because you will be focused on moving and killing. Ideal items are ones with the highest damaging output- AP has Deathfire Grasp or Rabaddons Cap, AD has Bloodthirster and Static Shiv.

Does this sound about right?