diff --git a/CHANGELOG.md b/CHANGELOG.md
index 719265202..b804bea27 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -45,6 +45,7 @@
 * [#2733](https://github.com/ruby-grape/grape/pull/2733): Drop the dead `active_support/core_ext/hash/reverse_merge` require; call `ActiveSupport::HashWithIndifferentAccess.new(...)` directly at call sites - [@ericproulx](https://github.com/ericproulx).
 * [#2734](https://github.com/ruby-grape/grape/pull/2734): Extract `options_route_enabled` from the Endpoint options Hash into a dedicated `attr_accessor` - [@ericproulx](https://github.com/ericproulx).
 * [#2736](https://github.com/ruby-grape/grape/pull/2736): Collapse `Endpoint#run_validators` rescue branches via `ValidationErrors` flatten; `ValidationErrors#initialize` keyword renamed `errors:` → `exceptions:` - [@ericproulx](https://github.com/ericproulx).
+* [#2749](https://github.com/ruby-grape/grape/pull/2749): Middleware tidy-up — dedupe `Versioner::Base#build_available_media_types` (was emitting `application/vnd.<vendor>-<version>` once per content_type) and assorted `Formatter` cleanups (guard clauses, in-place merges, drop a no-op splat) - [@ericproulx](https://github.com/ericproulx).
 * [#2746](https://github.com/ruby-grape/grape/pull/2746): Hoist `using:` / `except:` from `**opts` to explicit kwargs on `DSL::Parameters#requires` and `#optional` - [@ericproulx](https://github.com/ericproulx).
 * [#2742](https://github.com/ruby-grape/grape/pull/2742): Prune unused requires in `lib/grape.rb`; narrow `active_support/inflector` to `core_ext/string/inflections` - [@ericproulx](https://github.com/ericproulx).
 * [#2741](https://github.com/ruby-grape/grape/pull/2741): Readability pass: guard clauses and small extractions across `lib/` - [@ericproulx](https://github.com/ericproulx).
diff --git a/lib/grape/middleware/formatter.rb b/lib/grape/middleware/formatter.rb
index 51c660bff..ae9f05aef 100644
--- a/lib/grape/middleware/formatter.rb
+++ b/lib/grape/middleware/formatter.rb
@@ -33,7 +33,7 @@ def before
       def after
         return unless @app_response
 
-        status, headers, bodies = *@app_response
+        status, headers, bodies = @app_response
 
         return [status, headers, []] if Rack::Utils::STATUS_WITH_NO_ENTITY_BODY.include?(status)
 
@@ -73,7 +73,8 @@ def fetch_formatter(headers)
       def ensure_content_type(headers)
         return headers if headers[Rack::CONTENT_TYPE]
 
-        headers.merge(Rack::CONTENT_TYPE => content_type_for(env[Grape::Env::API_FORMAT]))
+        headers[Rack::CONTENT_TYPE] = content_type_for(env[Grape::Env::API_FORMAT])
+        headers
       end
 
       def read_body_input
@@ -105,11 +106,11 @@ def read_rack_input(body)
         begin
           body = (env[Grape::Env::API_REQUEST_BODY] = parser.call(body, env))
           if body.is_a?(Hash)
-            env[Rack::RACK_REQUEST_FORM_HASH] = if env.key?(Rack::RACK_REQUEST_FORM_HASH)
-                                                  env[Rack::RACK_REQUEST_FORM_HASH].merge(body)
-                                                else
-                                                  body
-                                                end
+            if (form_hash = env[Rack::RACK_REQUEST_FORM_HASH])
+              form_hash.merge!(body)
+            else
+              env[Rack::RACK_REQUEST_FORM_HASH] = body
+            end
             env[Rack::RACK_REQUEST_FORM_INPUT] = env[Rack::RACK_INPUT]
           end
         rescue Grape::Exceptions::Base => e
@@ -126,10 +127,11 @@ def read_rack_input(body)
       # - multipart/related
       # - multipart/mixed
       def read_body_input?
-        (rack_request.post? || rack_request.put? || rack_request.patch? || rack_request.delete?) &&
-          !(rack_request.form_data? && rack_request.content_type) &&
-          !rack_request.parseable_data? &&
-          (rack_request.content_length.to_i.positive? || rack_request.env['HTTP_TRANSFER_ENCODING'] == 'chunked')
+        return false unless rack_request.post? || rack_request.put? || rack_request.patch? || rack_request.delete?
+        return false if rack_request.form_data? && rack_request.content_type
+        return false if rack_request.parseable_data?
+
+        rack_request.content_length.to_i.positive? || rack_request.env['HTTP_TRANSFER_ENCODING'] == 'chunked'
       end
 
       def negotiate_content_type
diff --git a/lib/grape/middleware/versioner/base.rb b/lib/grape/middleware/versioner/base.rb
index 8b807e681..9f57664d7 100644
--- a/lib/grape/middleware/versioner/base.rb
+++ b/lib/grape/middleware/versioner/base.rb
@@ -50,14 +50,12 @@ def version_not_found!
         def build_available_media_types
           media_types = []
           base_media_type = "application/vnd.#{vendor}"
-          content_types.each_key do |extension|
-            versions&.reverse_each do |version|
-              media_types << "#{base_media_type}-#{version}+#{extension}"
-              media_types << "#{base_media_type}-#{version}"
-            end
-            media_types << "#{base_media_type}+#{extension}"
+          versions&.reverse_each do |version|
+            versioned_base = "#{base_media_type}-#{version}"
+            content_types.each_key { |extension| media_types << "#{versioned_base}+#{extension}" }
+            media_types << versioned_base
           end
-
+          content_types.each_key { |extension| media_types << "#{base_media_type}+#{extension}" }
           media_types << base_media_type
           media_types.concat(content_types.values.flatten)
           media_types