to hit rank 5 and above you have to play well, or simply broken decks like secret pala that doesnt really need to play around anything.

to play well u gotta play around cards, and identifying what kind of deck the opponent is playing. if the enemy is playing mage is it mech mage freeze mage mid range mage.
and the bot doesnt identify what staple cards are in the opposing deck thats why its harder to play around the enemy deck. so its really not surprising that the bot cant push above rank 5 with non top tier decks.
not to mention the bot doesnt play combo druid or combo decks in general which limits the number of viable decks that can push to rank 5 or past it.
as well as the needed tweaks like flooding the board with minions when enemy already played doomsayer or a mage that played explosive sheep.

well if im not wrong secret pala is the only deck that can hit rank 5 consistently

Yeah, the Project : NextGen thread is stickied at the top of this forum, kinda hard to miss it... Zoo Lock and Secret Pally are probably the easiest to rank high with the bot right now, Mech Mage and Face/Mid Hunters should also be pretty good. Beware though, from 10 to 5 it can be very random where it may win streak up to rank 5 or it may lose and bomb down 5 ranks, it depends a lot on whether the queue gives good matchups for your deck or not. If you run it every day in the final week of the month then it should eventually get rank 5 if the deck is good enough.

As long as the bot is not injecting or modifying hearthstone's files and improving its human-like behavior it will be harder for Blizzard to detect it, if not impossible.
It would be even possible for someone to make a smart AI for a few good decks and not only reach legend but qualify for on-site tournaments.

Moreover, Blizzard might be more suspicious of an account that only farms wins and auto-concedes around rank 20.

You are absolutely right my bad for being vague! You say that there are several but I say that there are 1 and truly 1 that gets you to rank 5 and that one is the secret paladin (Have not tried it yet but what I have read from the community)
I didnt say I am missing a lot of strong cards. I said for the new players to Hearthstone. I know that you need to have some cards to get higher in ranked play but that was not my point. My point is that hopefully both me and you know that you can get to rank 5 without so many cards in your arsenal if you play it manually and invest time in the game. What I am saying is that believe it or not I am deep-fully thankful to the programmers but there are yet many miles ahead. So hence the thread here for newcomers they now see that it doesn't work to just press start button on the bot and anticipate to get high in ranked play (I might be naive but I thought that by pressing the start button and getting some good mulligans, combos and settings I would get to rank 5).

About farming for gold and then playing arena or buy a pack is brilliant again I have to understate that I am not complaining. BUT and there is a BIG BUT you say that THEN you can build good decks and climb the ladder. Yes I can and many others can but they have to do it manually since as stated in the top of this post. There is only 1 that gets you to rank 5 and that is the secret paladin. (If you don't actually buy all the cards that are on that deck)