Perhaps fix it more properly after all :-)

doc/help/commands.asciidoc

@@ -685,6 +685,7 @@ How many steps to zoom out.
 [options="header",width="75%",cols="25%,75%"]
 |==============
 |Command|Description
+|<<clear-keychain,clear-keychain>>|Clear the currently entered key chain. 
 |<<command-accept,command-accept>>|Execute the command currently in the commandline.
 |<<command-history-next,command-history-next>>|Go forward in the commandline history.
 |<<command-history-prev,command-history-prev>>|Go back in the commandline history.
@@ -739,6 +740,10 @@ How many steps to zoom out.
 |<<toggle-selection,toggle-selection>>|Toggle caret selection mode.
 |<<yank-selected,yank-selected>>|Yank the selected text to the clipboard or primary selection.
 |==============
+[[clear-keychain]]
+=== clear-keychain
+Clear the currently entered key chain.
+
 [[command-accept]]
 === command-accept
 Execute the command currently in the commandline.

qutebrowser/config/configdata.py

@@ -1143,7 +1143,7 @@ KEY_DATA = collections.OrderedDict([
     ])),
 
     ('normal', collections.OrderedDict([
-        ('search', ['<Escape>']),
+        ('search ;; clear-keychain', ['<Escape>']),
         ('set-cmd-text -s :open', ['o']),
         ('set-cmd-text :open {url}', ['go']),
         ('set-cmd-text -s :open -t', ['O']),

qutebrowser/keyinput/basekeyparser.py

@@ -298,14 +298,6 @@ class BaseKeyParser(QObject):
         """
         handled = self._handle_special_key(e)
 
-        # Special case for <Esc>. See:
-        # https://github.com/The-Compiler/qutebrowser/issues/716
-        if e.key() == Qt.Key_Escape:
-            self._debug_log("Escape pressed, discarding '{}'.".format(
-                self._keystring))
-            self._keystring = ''
-            self.keystring_updated.emit(self._keystring)
-
         if handled or not self._supports_chains:
             return handled
         match = self._handle_single_key(e)
@@ -362,3 +354,9 @@ class BaseKeyParser(QObject):
                                  "defined!")
         if mode == self._modename:
             self.read_config()
+
+    def clear_keystring(self):
+        """Clear the currently entered key sequence."""
+        self._debug_log("discarding keystring '{}'.".format(self._keystring))
+        self._keystring = ''
+        self.keystring_updated.emit(self._keystring)

qutebrowser/keyinput/modeman.py

@@ -332,3 +332,8 @@ class ModeManager(QObject):
             return self._eventFilter_keypress(event)
         else:
             return self._eventFilter_keyrelease(event)
+
+    @cmdutils.register(instance='mode-manager', scope='window', hide=True)
+    def clear_keychain(self):
+        """Clear the currently entered key chain."""
+        self._handlers[self.mode].__self__.clear_keystring()