I can't see the ICC reversing Test status, they'd be better accepting there are too many Test sides and sides like Bangladesh will only slowly improve if they are constantly getting thrashed.
They need to play sides like New Zealand, Zimbabwe, West Indies and maybe even Ireland, Holland and Scotland to improve. They may still lose a lot of games, but it is like me playing John Higgins at snooker. I wouldn't learn a lot from playing him that I couldn't from watching him on TV, I'd be better off playing someone of my own standard or thereabouts.
When Bangladesh do play non-Test nations and lose, it does nothing to prove they are worth Test status. Sure they beat England recently, but when England weren't playing well and even then only just. If they were heading towards being good enough to merit Test status they would surely have not gone so long without winning a match in any form of cricket. Their record in Tests is attrocious, after 10 years they are still losing way too many, they should at least be drawing more - especially if, as you claim, bowling is their major weakness
Want to make a comparison with Sri Lanka? To give it a bit of substance I'll include last 11 series of Bangladesh against 11 series of Sri Lanka up to around the 10 year mark after their debut. Sri Lanka showed more fight much quicker than you give credit for,
Bangladesh (07/08 New Zealand - 2010 England)
Series : P10 W1 D0 L9 (Lost 90.00%)
Tests : P22 W2 D01 L19 (Won/Drew 13.64%)
Sri Lanka (85/86 India - 1991 England
Series : P10 W1 D3 L6 (Lost 60.00%)
Tests : P24 W2 D12 L10 (Won/Drew 58.33%)
A longer period for Sri Lanka, so Bangladesh at least have the benefit of more regular cricket. Bangladesh's only series win came over a much weakened West Indies side, not that West Indies are world beaters when at full strength these days.
Bangladesh's 35th Test was their first Test win, Sri Lanka's 14th produced their first victory. And to produce one last comparison, Bangladesh after all 68 of their Tests vs Sri Lanka and Zimbabwe after 68 Tests
Tests 1-68
Bangladesh : P68 W3 D6 L59 (Lost 86.76%)
Sri Lanka : P68 W9 D28 L31 (Lost 45.59%)
Zimbabwe : P68 W7 D23 L38 (Lost 55.88%)
Why lost percentage? It is simply to show that while Bangladesh might not be expected to win lots of Tests, they should at the very least be competitive after 10 years and not losing huge percentages of Tests. Their loss percentage for the last 11 series is 86.36% so less than half a percent different to their overall Test record ie little sign of improvement
While I acknowledge the volume of cricket at the moment makes a straight comparison difficult, it probably favours Bangladesh as they play more and get more regular (TV) income. They are by far the weakest of the three most recent Test additions, South Africa excepted as they were banned not recent debutants.
I guess the biggest advantage Zimbabwe and Sri Lanka had was they had a good bowler or two and some decent batsmen. Spread over bigger periods (92-04 and 82-97) they had longer for stars to come through. But even then the difference isn't massive, countered by the volume of matches and therefore experience. Zimbabwe had played 68 Tests in only a period of a couple of years more, Sri Lanka maybe profitting from five extra years, but for Sri Lanka half of their first 68 Tests came in the last six years of that 15 year period.
Even without comparison, Bangladesh should not be losing over 80% of their Tests - still or overall. Maybe it is a reflection of the impact of too much ODI and T20 cricket, but it's the same for everyone. The best hope I have for Bangladesh is they stick with the young side/players they have, but the batsmen need to apply themselves more and the bowlers either need to improve or they need to find a top wicket taking threat from somewhere. Are they any closer to being a competitive Test side than they were on debut? I fear not. They made 400 exactly in their first ever Test innings, how many times have they done that since? Having India 236/6 in reply they looked like they might even gain a 1st innings lead, they didn't quite manage it and got skittled for 91.
And for their three Tests wins, none is terribly convincing. A win over a Zimbabwe side about to desist as a Test playing side with all its troubles, and two over a depleted West Indies side. Sri Lanka's first win was over India, Zimbabwe's over Pakistan, a Pakistan side including Saaed Anwar, Aamir Sohail, Salim Malik, Rashid Latif, Inzamam Ul Haq, Wasim Akram and Aqib Javed so far from a depleted side.
HowSTAT! Match Scorecard